Tivaware Library - Unrecognized Compiler

When compiling the Tivaware USB library in ccs, you get an error "Unrecognized compiler" emitted by usblib.h if the constant ccs is not defined.  Additionally, the library requires the --gcc flag to be present in order to compile.  It seems like compiling a TI library on a TI compiler should do better.  These trivial changes should be implemented in the next release: 

1. Check for a compiler flag that gets set automatically by the compiler like __TI_ARM__ or __TI_COMPILER_VERSION__ instead of one you have to set manually like ccs

2. Check for the __TI_GNU_ATTRIBUTE_SUPPORT__ attribute and emit an error if it isn't present

#if defined(codered) ||                                                       \
    defined(gcc) ||                                                           \
    defined(rvmdk) ||                                                         \
    defined(__ARMCC_VERSION) ||                                               \
    defined(sourcerygxx)
	#define PACKED __attribute__ ((packed))
#elif defined(__TI_COMPILER_VERSION__)
   #ifdef __TI_GNU_ATTRIBUTE_SUPPORT__
		#define PACKED __attribute__ ((packed))
   #else
        #error  The usblib requires the --gcc compiler flag.  Please set the flag on \
				the command line or in the ccs ide at Project->Properties->Build->   \
				ArmCompiler->Advanced Options->Language Options->Enable Support For  \
				GCC Extensions
	#endif
#elif defined(ewarm)
    #define PACKED
#else
    #error Unrecognized COMPILER!
#endif