Implement independent instances.

Previously, most of the classes were implemented as singletons so only one
instance was possible.

This change adds an instance handle-based API.  In Java, this API is located
in a different package than the old API (edu.wpi.first.networktables).

Backwards compatibility with ITable and the old NetworkTable API is largely
maintained, but a handful of classes have moved to the new package in Java
(ConnectionInfo and PersistentException), and the old JNI has been completed
replaced.

Also:
- Move SetTeam implementation to Dispatcher.
- Consistently pass time through Java and C++ Value API.
- Rename nt_Value.h to NetworkTableValue.h for consistency with Java.
- Improve documentation
- Make C++ and Java APIs more consistent
- Document RPC functions and support RPC in Java.
- Add polling features for entry and connection listeners and use them to
  move callback threads to Java level.
- Remove thread start and stop hooks (as polling is available).
- Make Notifiers, RpcServer, Dispatcher, and Storage mockable.
- Set NOTIFY_NEW on immediate entry notifications.
- Make GetTable("/") and GetTable("") equivalent.
- Generate local notification for flags update when loading persistent file.

And many unit test updates/changes:
- Use InitGoogleMock instead of InitGoogleTest in test main.
- Move test printers to TestPrinter.h/cpp.
- Provide printers for StringRef, EntryNotifier, and Handle.
- StorageTest: Check notifications.
- Add entry notifier unit tests.
- Storage: Add test for incoming entry assignment.
- Update connection listener tests.
- Add entry listener unit tests.

Fixes #11, #140, #189, #190, #192, #193, #221

src/main/native/cpp/EntryNotifier.h

@@ -0,0 +1,108 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2015. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef NT_ENTRYNOTIFIER_H_
+#define NT_ENTRYNOTIFIER_H_
+
+#include "ntcore_cpp.h"
+
+#include <atomic>
+
+#include "CallbackManager.h"
+#include "Handle.h"
+#include "IEntryNotifier.h"
+
+namespace wpi {
+class Logger;
+}
+
+namespace nt {
+
+namespace impl {
+
+struct EntryListenerData
+    : public ListenerData<std::function<void(const EntryNotification& event)>> {
+  EntryListenerData() = default;
+  EntryListenerData(
+      std::function<void(const EntryNotification& event)> callback_,
+      StringRef prefix_, unsigned int flags_)
+      : ListenerData(callback_), prefix(prefix_), flags(flags_) {}
+  EntryListenerData(
+      std::function<void(const EntryNotification& event)> callback_,
+      NT_Entry entry_, unsigned int flags_)
+      : ListenerData(callback_), entry(entry_), flags(flags_) {}
+  EntryListenerData(unsigned int poller_uid_, StringRef prefix_,
+                    unsigned int flags_)
+      : ListenerData(poller_uid_), prefix(prefix_), flags(flags_) {}
+  EntryListenerData(unsigned int poller_uid_, NT_Entry entry_,
+                    unsigned int flags_)
+      : ListenerData(poller_uid_), entry(entry_), flags(flags_) {}
+
+  std::string prefix;
+  NT_Entry entry = 0;
+  unsigned int flags;
+};
+
+class EntryNotifierThread
+    : public CallbackThread<EntryNotifierThread, EntryNotification,
+                            EntryListenerData> {
+ public:
+  EntryNotifierThread(int inst) : m_inst(inst) {}
+
+  bool Matches(const EntryListenerData& listener,
+               const EntryNotification& data);
+
+  void SetListener(EntryNotification* data, unsigned int listener_uid) {
+    data->listener =
+        Handle(m_inst, listener_uid, Handle::kEntryListener).handle();
+  }
+
+  void DoCallback(std::function<void(const EntryNotification& event)> callback,
+                  const EntryNotification& data) {
+    callback(data);
+  }
+
+  int m_inst;
+};
+
+}  // namespace impl
+
+class EntryNotifier
+    : public IEntryNotifier,
+      public CallbackManager<EntryNotifier, impl::EntryNotifierThread> {
+  friend class EntryNotifierTest;
+  friend class CallbackManager<EntryNotifier, impl::EntryNotifierThread>;
+
+ public:
+  explicit EntryNotifier(int inst, wpi::Logger& logger);
+
+  void Start();
+
+  bool local_notifiers() const override;
+
+  unsigned int Add(std::function<void(const EntryNotification& event)> callback,
+                   llvm::StringRef prefix, unsigned int flags);
+  unsigned int Add(std::function<void(const EntryNotification& event)> callback,
+                   unsigned int local_id, unsigned int flags);
+  unsigned int AddPolled(unsigned int poller_uid, llvm::StringRef prefix,
+                         unsigned int flags);
+  unsigned int AddPolled(unsigned int poller_uid, unsigned int local_id,
+                         unsigned int flags);
+
+  void NotifyEntry(unsigned int local_id, StringRef name,
+                   std::shared_ptr<Value> value, unsigned int flags,
+                   unsigned int only_listener = UINT_MAX) override;
+
+ private:
+  int m_inst;
+  wpi::Logger& m_logger;
+  std::atomic_bool m_local_notifiers;
+};
+
+}  // namespace nt
+
+#endif  // NT_ENTRYNOTIFIER_H_