added Serbian translation
fixed Serbian translation for older Firefox OS versions (eg 1.2)
fixed small typo in Serbian latin translation
add LICENSE file
input:active (and .active) should use better color (fixes issue #78)
Merge pull request #88 from MichaelKohler/mpl

add LICENSE file
Merge pull request #85 from djura-san/master

Added Serbian translation (latin and cyrillic)
Merge pull request #90 from MichaelKohler/backgroundcolor

input:active (and .active) should use better color (fixes issue #78)
add DEL button to delete last inputted number (fixes issue #64)
Merge branch 'deletion' of github.com:MichaelKohler/calculator into deletion