Compatibility with Bootstrap 3

This is a basic/hacky compatibility update. I essentially made the diff between bootstrap-modal 2.1 JS files and Bootstrap 3's modal.js, then merged them.

Some features of Bootstrap modal may be broken, but it seems to work for the most at this point.

I'll keep this branch updated as soon as I identify something missing. I'm sorry I could not completely review the code to ensure it was rightfully done, but I hope it may help with starting the update.