board/pca1000x: added/fixed dist scripts

- pca10000: added author to debug.sh
- pca10005: added debug and reset scripts
- pca10005: fixed flash script
- pca10005: adjusted env vars in Makefile.include
unittests: make: Fix unittests for branch changes

Changing between branches in git typically leaves directories empty and
does not remove them. If you have different unittests in different
branches this leads to an error in building them, since the current
configuration expects a Makefile in all `tests-*` directory. This change
configures Make to search for a Makefile in `tests-*` rather than just
assuming that there is one.
rpl: mute RPL

Removes all but one occurrence of printf and puts within routing (the
remaining puts is called from a debug function.
add backspace functionality in shell
test:cbor: supress warnings about nan/infty
Travis: enable apt caching

This should speed up the installation process a bit.
Merge pull request #1689 from LudwigOrtmann/issue-1636-p1

Travis: enable apt caching
Travis: merge install commands
Merge pull request #1691 from LudwigOrtmann/issue-1636-p2

Travis: merge install commands
Merge pull request #1688 from N8Fear/naninarith

lint: supress warnings about nan/infty in arithmetics in the CBOR unit tests
Add 0x7f as backspace key in shell
board/cpu: added SPI driver for stm32f0discovery
[SQUASH ME] finished 0.1 of spi driver
SPI: more fixes including DEBUG info
cpu: mini cleanup to spi driver
tests: added periph_spi test
[SQUASH ME] tests/periph_spi: rewrote test
[SQUASH ME] stm32f0: substantial fixes to SPI driver
[SQUASH ME] test: guard if no SPI device defined
[SQUASH ME] test: fixed according to updated GPIO interface