Changes -ms-flex-pack from center to distribute

- Fixes #426
- Fixes indentation
Removes prefixer from border radius shorthand mixin
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.
FIX #556 refactor word-wrap

word-wrap is now overflow-wrap fallback and word-break gets reset
accordingly depending on $wrap