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/src/SmartDashboard/SmartDashboard.cpp

@@ -12,6 +12,8 @@
 #include "WPIErrors.h"
 #include "networktables/NetworkTable.h"
 
+using namespace frc;
+
 std::shared_ptr<ITable> SmartDashboard::m_table;
 std::map<std::shared_ptr<ITable>, Sendable*> SmartDashboard::m_tablesToData;