board/mbed_lpc1768 changed the serial device to UART0
                   -> enables USB/serial communication
Revert "tests: don't build test/libfixmath on Travis CI"

This reverts commit f061d0214ebb788b3262b312a80323f5a1473d27.
periph/rtc: move struct tm note to the top

The remark is valid for the whole interface, not just `rtc_get_time`.
Merge pull request #2201 from BytesGalore/mbed_lpc1768_uartUSB

board/mbed_lpc1768 changed the serial device to UART0
Merge pull request #2193 from LudwigOrtmann/libfixmath-test

Revert "tests: don't build test/libfixmath on Travis CI"
Merge pull request #2205 from LudwigOrtmann/periph-rtc-doc

periph/rtc: move struct tm note to the top