Add root attribute to google-api-loader

Allows override appId and thus makes it possible to load an API
from an arbitrary URL, including dev App Engine server.
Initialize both appId and root attr to null
Merge pull request #23 from crhym3/root-attr

Add root attribute to google-api-loader
bower.json: update to 0.3.4
Add API docs
Merge pull request #28 from GoogleWebComponents/fix15

Add API docs
Update to polymer 0.5.0
Fix urls
Rev polymer to 0.5.1
Add langugage param
Add note on docs
Merge pull request #30 from GoogleWebComponents/addlang

Add langugage param
Release 0.4.3
Enables sign-in
Merge pull request #32 from L1eselB/master

Enables sign-in fixes issue #31