Update maintenence validation target to also generate Atmel Studio integration files.

git-svn-id: http://lufa-lib.googlecode.com/svn/trunk@2522 d5102386-fcda-11dd-9fdb-3debd5008f28
Add missing include to the USB driver core mode header file.

git-svn-id: http://lufa-lib.googlecode.com/svn/trunk@2523 d5102386-fcda-11dd-9fdb-3debd5008f28
Minor documentation improvements.

git-svn-id: http://lufa-lib.googlecode.com/svn/trunk@2524 d5102386-fcda-11dd-9fdb-3debd5008f28
Split up USB source files in lufa_sources.mk build system module so that applications can pull in mode-specific USB support rather than having to compile all files even if it is known they will not be used.

git-svn-id: http://lufa-lib.googlecode.com/svn/trunk@2525 d5102386-fcda-11dd-9fdb-3debd5008f28