Cleaning up npm/bower dependencies and grunt tasks

- Removed unneeded dependencies and updated needed dependencies in
package.json and bower.json
- Cleaned up package.json and bower.json
- Remove unneeded “relaxing” options and added some “enforcing” options
in .jshintrc
- Updated angularfire.js to conform to new .jshintrc options
- Removed changelog task from grunt
- Removed CasperJS link in README
I'm fine changing all quotes to single quotes if that's what you prefer. I don't have a preference either way and just did double since most of angularfire already had double. I just think we should be consistent throughout the file. Is that a fair compromise?