Implement core unittests
unittests: Move tests-core into subdirectoy
Merge pull request #961 from authmillenon/core-unittests

unittests: Unittests for core module data strutures
fixed printf specifiers
sys/ping/ping.c: malloc size of type, not size of pointer
native: unify license headers
native/tramp.S: add missing license header
documentation: append my email to my name everywhere
Merge pull request #1143 from jan-schreib/static-code-analyser-cleanup

 sys/ping/ping.c: malloc size of type, not size of pointer
Merge pull request #1184 from LudwigOrtmann/native_license_unification

Native license unification
fixed initializer and Wformat warnings
Merge pull request #1094 from BytesGalore/fix_print_format_warnings_test_vtimer

test:test_vtimer fixed initializer and Wformat warnings
make: print error if make was executed in the root

Fixes #1104, alternative to #1178.
Merge pull request #1183 from Kijewski/issue-1104

make: print error if make was executed in the root
make: remove clutter

Remove some outdated example code, and simplify output folder creation.
make: parallelize creation of board and base code
 make: add `BOARD_INSUFFICIENT_RAM` blacklisting

Currently most blacklistings for examples and tests are done because the
board provides too little RAM or ROM. Besides of the actual linking all
the compiling should nevertheless work just fine.

This PR adds the variable `BOARD_INSUFFICIENT_RAM` to tell the
`buildtest` to compile the code for a board, but omit the linking step.
Use `BOARD_INSUFFICIENT_RAM` in examples and tests