URBNG-469: Register and login functionality
Made some of suggested changes.
Added check for empty json in isValid method.
Merge branch 'android' of github.com:element31/UrbanGame into login_register
Merge pull request #159 from KamilLelonek/android

[Android][URBNG-73] Completed
Made some suggested changes
Merge branch 'android' of github.com:blstream/UrbanGame into login_register
Added class to handle templated uris.
Fixed bug with null error messages.
Bug fix
Merge pull request #155 from element31/login_register

[Android] URBNG-469: Register and login