boards: created periph-conf.h for remaining boards
cc430: lpc2387: switch to new periph/rtc interface

Removes the old interface.
rtc: cleanup of lpc2387-rtc implementation
cpu: remove superfluous gettimeofday functions
cpu: lpc2387: further rtc cleanup
periph_rtc: streamline lpc2387 and cc430 naming
travis: make travis happy for empty header files
pttu: add periph_rtc also to this MSB-A2 variant