cpu: added low-level pwm driver impl for lpc2387
boards: added periph_conf.h for msba2 and avsextrem
drivers: some adjustments to low-level pwm driver

- adjusted doxygen and boilerplate
- changed return values for start and stop functions
board - pttu: added periph_conf.h
make: s/PROJDEPS/APPDEPS/

fixes https://github.com/RIOT-OS/RIOT/issues/1284
doc: improve APPDEPS example

Addresses https://github.com/RIOT-OS/RIOT/pull/1339#discussion_r14050325
make: evaluate the Git SHA only once
Merge pull request #1339 from LudwigOrtmann/issue-1284

make: s/PROJDEPS/APPDEPS/
Merge pull request #1340 from Kijewski/evaluate-git-sha-once

make: evaluate the Git SHA only once
Merge pull request #1318 from haukepetersen/msba2_pwm

cpu: added low-level PWM driver for the lpc2387
sys: added color module
Merge pull request #1315 from haukepetersen/add_sys_color

sys: added color module