Add XMEGA C3 family to the ModuleTest build test.

Remove unnecessary GCC_MEMORY_BARRIER() at the end of GetGlobalInterruptMask().

Minor documentation improvements.

LUFA/Common/Common.h

@@ -293,8 +293,6 @@
 				#elif (ARCH == ARCH_XMEGA)
 				return SREG;
 				#endif
-
-				GCC_MEMORY_BARRIER();
 			}
 
 			/** Sets the global interrupt enable state of the microcontroller to the mask passed into the function.

LUFA/License.txt

@@ -15,4 +15,3 @@ whatsoever resulting from loss of use, data or profits, whether
 in an action of contract, negligence or other tortious action,
 arising out of or in connection with the use or performance of
 this software.
-