Move version constants into its own compile-unit

Speeds up the build by moving those constants into a separate compile-unit.
Currently, since the version header is auto regenerated on each build,
all modules that include it, also have to be recompiled every time.

lib/FirmwareVersion/include/FirmwareVersion.h

@@ -0,0 +1,12 @@
+#ifndef _FIRMWARE_VERSION_h
+#define _FIRMWARE_VERSION_h
+
+
+class FirmwareVersion {
+public:
+	static long BuildEpoch;
+	static const char* VersionString;
+};
+
+#endif
+