Fix too short 6LoWPAN reassembly timeout
[avr] Removed usage of deprecated MCUSR

Since avr-libc 1.8.0 MCUSR is marked as poison as it was replaced by the
correct name MCUCSR.
Thus code still using the old MCUSR name does not compile anymore.

This commit replaces usages of former MCUSR by its new name MCUCSR and
modifies the alias fallback accordingly.
llsec: Renamed ccm to ccm_star & Renamed llsec regression test
Makefile.include: Assign git description variable once.

By changing RELSTR= into RELSTR:= we force Make to evaluate the Git
version string only during Makefile read, and not on every single build
command execution.

The reduction in file system I/O cut the time to build
examples/er-rest-example on my development machine by a significant
amount, see below.

Core i7 notebook with ext4 file system on an SSD (building for TARGET=mulle):
"RELSTR="  make  19.70s user 1.07s system 82% cpu 25.291 total
"RELSTR:=" make  11.81s user 1.27s system 79% cpu 16.499 total

Signed-off-by: Joakim Gebart <joakim.gebart@eistec.se>
Merge pull request #841 from gebart/build-git-tag-io-reduce

Makefile.include: Reduce I/O load (and build time) by assigning git description variable once.
[cooja-platform] Include eeprom.h to avoid implicit declaration warning
[cooja-platform] Remove unused variable 'shortaddr'

This variable was set but never used in the code
[cooja-platform] Add cast to linkaddr_t to avoid warning
[cooja-platform] Fixes for slip-bridge compatibility

* Added dev/uart1.h header file to cooja platform
* Added slip arch stub
* Suppress examples putchar definition as cooja platform provides its own

Note that the uart1.h file should only be an intermediate solution.
A generic contiki-wide definition for uart handling is required as each
platform defines its own varying set of uart functions.
Button: Move common interface visualization to Button class

The implementation of a simple JPanel with a JButton was only code
duplication accross the several button implementations.
SkyButton: Reduce dependency on SkyMote

Placed call to setButton() in implementation-specific functions
doPressButton() and doReleaseButton() as in ContikiButton.
Button: None of the buttons will saves its state

Saving a buttons state in simulation file is not required as its state
is much too volatile.
Button: Add doPressButton() and doReleaseButton() to Button class

As every Button has a node-specific implementation part, this should be
the minimal interface to the backend node emulator for pressing and
releasing a button.
Buttons: Move implementation of button routines to Button class

The implementation of clickButton(), pressButton(), and releaseButton()
can be shared accross the several node-dependent implementations as
they use the node-dependent doPressButton() doReleaseButton() routines.
Buttons: Added missing @Override annotations
Buttons: Some minor cleanups

Removed imports not required anymore and made some class members final
Buttons: use non-deprecated MSPSim button api
Merge pull request #846 from ejoerns/pull-req/cooja-platform

Cooja platform fixes
New PluginType SIM_CONTROL_PLUGIN for sim control

SIM_CONTROL_PLGUIN are handled like SIM_PLUGIN, with one exception.
If the simulation is started with -nogui=<simfile> than it is checked
if a controlling plugin is loaded. If not, the simulation terminates
with an error message.
Better error message when aborting simulation