[SQUASHME] pkg: added desvirt

(and removed desvirt from example/clocksync/dist)
Just forgotten the checks of the PIDs
[SQUASHME] clocksync: send and receiver helper fixed
[SQUASHME] clocksync: fixed code style issues
[SQUASHME] clocksync: create threads with CREATE_SLEEPING
[SQUASHME] clocksync/gtsp: replaced literals by defines
[SQUASHME] examples/clocksync: use uart0_readc/uart0_putc
[SQUASHME] clocksync/includes: added and fixed documentation
[SQUASHME] gtimer/Makefile: EOF fix for git