Update bower.json ignore since #480
Update bower.json ignore since #480

Since ./dist is removed, app is necessary for importing the files
when bourbon is loaded via bower, thus shouldn't be ignored.

Jazz-Man/bourbon,mindeavor/bourbon,setie/bourbon,ismarkunc/bourbon,Nikeshsuwal/bourbon,setie/bourbon,zyj1022/bourbon,nickg33/bourbon,thoughtbot/bourbon,jasonwalkow/bourbon,mindeavor/bourbon,nagyistoce/sass-bourbon.io,nickg33/bourbon,chriseppstein/bourbon,craftsmen/bourbon,Jazz-Man/bourbon,jasonwalkow/bourbon,zyj1022/bourbon,cllns/bourbon,smithdamen/bourbon,craftsmen/bourbon,smithdamen/bourbon,greyhwndz/bourbon,greyhwndz/bourbon,chriseppstein/bourbon,thoughtbot/bourbon