Added 'plist' command to bin/build-i18n.js and tests.

This command outputs a plist file for the given i18n bundle module.

Transifex doesn't currently support requirejs i18n bundles, and the
Apple plist format appears to be the closest thing to it.
Added config.githubBranch to require config, made github URLs more DRY.
Added a	very early bin/transifex.js and	test suite.

The script doesn't really do anything yet other	than display some
information about the project.

Also added request as a dependency to package.json, as we use it to
communicate with transifex's REST API.
added more functions to transifex.js with tests.
wrote network-side part of importing from transifex.
finished initial implementation of transifex.js.
added examples/transifex.html and instructions for localization to readme.
Added --i18n-url option to build-require.js.
transifex.html now optionally uses transifex-to-requirejs-i18n-server.

This makes it easy for folks to test out their localization in Friendlycode
without needing to clone the git repo.
added locale selection widget and querystring arg to examples/transifex.html.
Moved github-related keys from require-config.js to package.json.

I tried to use the "repository" key in package.json described here:

https://npmjs.org/doc/json.html#repository

The use of 'repository.defaultBranch' is my own invention, though,
which is hopefully acceptable.
Merge pull request #175 from toolness/transifex

Add support for Transifex localizations