Import TRACE_EVENT macro from the kernel v3

This is a slightly modified version of the TRACE_EVENT
macro from the kernel, TP_printf has replaced TP_printk.

The TRACE_EVENT macro expansion is currently a dummy which
only expands to a printf probe, connected in a constructor.

Changes since version 2:
Added re-licensing information
Macro naming is more consisten (always contains trace)

Changes since version 1:
Added new headers to include/Makefile.am
Added major copyright holders and license information to headers.