Custom styling bootstrap buttons

I wanted to change the bootstrap buttons classes. I could only changed the templates, but i thought it would be better to be able to customize them. I´m a newbie with github and angular. Sorry for the misconceptions.

The first commit is for correcting a claerfix typo.

The next commits are for customizing the bootstrap buttons classes.

I wanted to create separated pull requests. Instead i created a pull request for my development branch. 
:-(