Namespace all wpilibc functions/classes into "frc" namespace. (#311)

Base.h provides a backwards compatibility shim (enabled unless
NAMESPACED_WPILIB is defined) that does a "using namespace frc".
However, as some header files do not include Base.h, this may
be a breaking change in some corner cases (with an easy fix).

Fixes #218.

wpilibc/shared/include/LiveWindow/LiveWindow.h

@@ -16,6 +16,8 @@
 #include "LiveWindow/LiveWindowSendable.h"
 #include "tables/ITable.h"
 
+namespace frc {
+
 struct LiveWindowComponent {
   std::string subsystem;
   std::string name;
@@ -81,3 +83,5 @@ class LiveWindow {
   bool m_enabled = false;
   bool m_firstTime = true;
 };
+
+}  // namespace frc

wpilibc/shared/include/LiveWindow/LiveWindowSendable.h

@@ -9,6 +9,8 @@
 
 #include "SmartDashboard/Sendable.h"
 
+namespace frc {
+
 /**
  * Live Window Sendable is a special type of object sendable to the live window.
  */
@@ -32,3 +34,5 @@ class LiveWindowSendable : public Sendable {
    */
   virtual void StopLiveWindowMode() = 0;
 };
+
+}  // namespace frc

wpilibc/shared/include/LiveWindow/LiveWindowStatusListener.h

@@ -12,8 +12,12 @@
 #include "tables/ITable.h"
 #include "tables/ITableListener.h"
 
+namespace frc {
+
 class LiveWindowStatusListener : public ITableListener {
  public:
   virtual void ValueChanged(ITable* source, llvm::StringRef key,
                             std::shared_ptr<nt::Value> value, bool isNew);
 };
+
+}  // namespace frc