board/f4vi1: enabled support for C++
ignore IDEA project files
Merge pull request #2055 from MatthiasLohr/ignore-idea

ignore IDEA project files
Merge pull request #2035 from haukepetersen/fix_f4vi1_cpp

board/f4vi1: enabled support for C++
Travis: use different emdebian mirror for now
Merge pull request #2057 from LudwigOrtmann/emdebian

Travis: use different emdebian mirror for now
boards/samr21-xpro: declare implemented features