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
- Removed link to license
Removed "quotmark" requirement during linting
Merge pull request #321 from firebase/clean_up_dependencies

Cleaning up npm/bower dependencies and grunt tasks