Update ModuleTest build test to enable new warnings supported in the latest Atmel Toolchain release's included AVR-GCC version.

Add help text to the project makefiles to help new users get information on the improved build system.

Add DEBUG_FORMAT and DEBUG_LEVEL optional parameters to the BUILD module. Turn off generation of debug information when performing a validation build, and when running the build tests.

Rename build system module makefiles from "lufa.MODULE.in" to "lufa_MODULE.mk" to prevent makefile from assuming the include is an old style build rule, slowing down the build process.

Prevent the BUILD module from shell-executing multiple processes to determine the avr-size flags to speed up the build, unless the size rule is invoked.

Add warnings and set warnings as errors to the SingleUSBModeTest build test makefile.

Fix project makefiles - remove trailing slash from LUFA_PATH entries and the XPLAINBridge project AVRISP file include path to prevent build errors.

Strip out BuildTest sub-makefile contents as much as possible. Remove old UC3 build test makefile from the ModuleTest build test. Add platform module to the example LUFA makefile.

Add C_FLAGS, CPP_FLAGS and ASM_FLAGS variables to the build system BUILD module to allow for language-specific compiler/assembler flags.

Replace architecture specific makefiles in the BuildTests with the new common build system makefiles.