Include css/bootstrap.css bower.json in "main"

[hoppy-kamper]

I noticed this was missing when trying to do a grunt build with Yeoman scaffold. It looks like the css reference was mistakenly taken out when the font files were removed. See Bootstraps bower.json https://github.com/twbs/bootstrap/blob/master/bower.json

[dbtek]

Hi @Kamps-Duac,

Thanks for the PR. I think you missed that there is no css file in main section. With bootstrap/16359 css & font files are removed from main to comply with bower spec.

This project as a bootstrap distribution follows same approach. Override method @moravcik suggested on #27 could be useful for those using tools like wiredep.

Edit: wrong credit.

[hoppy-kamper]

K thanks!