use mutex in vtimer_sleep

this change prevents a race condition in case of
short sleep time

Fixes: https://github.com/RIOT-OS/RIOT/issues/550
added the missing define for radio_packet_length_t on econotag
timex.c: add copyright header
tests: use astyle to adopt current code style guide
Allow Mac linebreaks in shell

QEMU uses Mac style newlines in its UART implementation.
This change allows Unix ("\n"), DOS ("\r\n") and Mac ("\r") style
linebreaks.
use one consistent mail address in all places
update Kaspar's email address

kaspar.schleiser@fu-berlin.de is obsolete.
(2nd try, first try was overwritten by some overzealous documenter)
fix libcoap checkout target

Fixes the following error:
make[1]: Entering directory '/foo/RIOT/pkg/libcoap'
git clone http://git.code.sf.net/p/libcoap/code /foo/RIOT/pkg/libcoap/libcoap && \
	cd /foo/RIOT/pkg/libcoap/libcoap && git checkout 89acaa6775ca3a4aedea510557e6b9c0c01fa5db
fatal: destination path '/foo/RIOT/pkg/libcoap/libcoap' already exists and is not an empty directory.
Makefile:25: recipe for target '/foo/RIOT/pkg/libcoap/libcoap' failed
add .gitignore for openwsn pkg
examples: use astyle to adopt current code style guide
fix call to err()
handle select errors EAGAIN | EWOULDBLOCK in lpm
handle some should-be impossible paths
guard swapcontext in _native_syscall_leave
handle more errors and remove race condition in native_isr_entry
Don't unblock signals again.

A late signal could kill the process otherwise.
guard setitimer
block all signals per default
force-debug (eINT && in_isr) in DEVELHELP
dont err() but warn() if no thread exists in native_isr_entry