Add bower.json

This file allows this package to be installed using Bower. I have
registered the package as `method-proxy-js` in the bower package
registry. It can now be installed by executing:

  bower install method-proxy-js

More information on Bower can be found at:

  https://github.com/bower/bower
  http://bower.io/

Change-Id: Ic9390da8c10dcd16013e2860825b4d84bb514308
Reviewed-on: https://gerrit.causes.com/26223
Tested-by: Joe Lencioni <joe.lencioni@causes.com>
Reviewed-by: Joe Lencioni <joe.lencioni@causes.com>