shell: print command if not found
shell: fixup test_shell expect scripts
shell: fix newlines
x86: add read-before-write check at runtime

Finding read-before-writes statically is quite difficult. In native we
can use valgrind, but on boards without an MMU we are out of luck.

x86 has an MMU, let's use it.

If `-DDEBUG_READ_BEFORE_WRITE` was set, then pages on the heap get
initialized upon first use. If the page was read before written, then a
debug message with the virtual and physical address of the memory
location is printed, as well as the address of the offending instruction.
you can never have enough debugging in RPL
some minor fixes and debugging
set correct transceiver stack size for debugging
fixed debugging for cc110x
net: IPv6: RPL: more debug output
rpl: debug: use DEBUGF where necessary
tests: add test_vtimer_msg_diff

This test sets three timers and renews them periodically, showing the
difference they accumulate.
tests: test_vtimer_msg_diff: use array for timers, change first to 1s
tests: test_vtimer_msg_diff: add some timers, change max values
tests: test_vtimer_msg_diff: Makefile s/PROJECT/APPLICATION/g
x86: slightly better debuggable bincode

While tracking down an error in #1253 I ameded newlib a bit to be
slightly better debuggable. Some lengthy macros were removed in favor of
proper functions.

The parameter passing was wrong before (because of a bug in newlib),
because the user provided CFLAGS were overwritten in the subfolders.
It is kinda strange that this did not cause errors.

The standalone version of the toolchain script was deleted, because it
is not reasonable to maintain two scripts.
x86: Use 'versioning' for precompiled newlib
core: remove unnecessary tests in sched.c

The scheduling gets activated by `kernel_init()` calling
`cpu_switch_context_exit()`. Before this `sched_run()` won't be called.
When it gets called, at least the main thread and the idle thread are
spawned. The idle thread won't die / get killed. So there always is at
least one thread in `runqueue_bitcache`.

Closes #19.
cpu: added low-level pwm driver impl for lpc2387
boards: added periph_conf.h for msba2 and avsextrem
drivers: added rgbled driver