Minor documentation improvements, update integration DLL.
Added missing LEDs to the XMEGA A3BU Xplained and XMEGA C3 Xplained board LED drivers
Ensure core library documentation sections use unique IDs.
Clean up Doxygen to Docbook XSLT, update Atmel Studio blob to use the new IDs.
Add maintenance makefile rule to detect oversize code lines.
Force-disable the inbuilt makefile rules as well as suffixes in the core build system makefile.
Minor documentation improvements.