Allow module to be bundled with browserify and webpack. Fixes #9

[dstreet]

With this change, you can now require('rpc-websockets') in your browser builds. This will be correctly resolved to the browser client only when using browserify or webpack.

There are a couple notable changes:

• The distributed browser build is now located at dist/index.browser-bundle.js.
• The API for the browser build matches the server-side build, where Client is exported from the main module, rather than the Client constructor being the default export.
• src/lib/client.js now exports a factory function to allow for a websocket dependency to be injected. This greatly simplified the isomorphic build process

[coveralls]

Coverage increased (+0.02%) to 90.608% when pulling 4d1599a on dstreet:browser-bundle into ee4b8a3 on qaap:master.

[coveralls]

Coverage increased (+0.02%) to 90.608% when pulling 4d1599a on dstreet:browser-bundle into ee4b8a3 on qaap:master.