Changed const char* -> string in most of wpilibc.

The HAL will remain untouched in order to maintain C-style
compatibility. A few places in wpilibc were left as
C-style strings, especially if special formatting (eg,
elaborate uses of snprintf or sscanf) was being used.

In general, const char* was changed to std::string.
character buffers used for formatting were either
untouched, changed to std::stringstream, or changed
to std::string, depending on what was done with
the buffer.

Change-Id: I5e431ddf1cc4d9a6d534e1f21b16ea23be26e7f1

wpilibc/wpilibC++IntegrationTests/src/command/CommandTest.cpp

@@ -44,7 +44,7 @@ class ASubsystem : public Subsystem {
   Command *m_command = nullptr;
 
  public:
-  ASubsystem(const char *name) : Subsystem(name) {}
+  ASubsystem(const std::string &name) : Subsystem(name) {}
 
   virtual void InitDefaultCommand() override {
     if (m_command != nullptr) {