Create bower.json to support proper bower dependencies

Added bower.json, make bower to utilize this configuration file to configure simditor angular wrapper and simditor-all.js together in one shot.
This is the first step to make sure this package compatible with bower specification.

However, the next step, the better way to utilize bower, is to remove all sources from simditor, instead, put simditor as dependencies under bower.json.
Merge pull request #7 from realdah/master

Create bower.json to support proper bower dependencies