Added links to Google ToS and dev guides.
Added links to Google ToS and dev guides.

slb235/GAPlugin,khalidb91/GAPlugin,bobeast/GAPlugin,leothenerd/GAPlugin,phpsa/GAPlugin,neilrackett/cordova-plugin-ga,bobeast/GAPlugin,phonegap-build/GAPlugin,slb235/GAPlugin,leothenerd/GAPlugin,phpsa/GAPlugin,slb235/GAPlugin,phpsa/GAPlugin,leothenerd/GAPlugin,phonegap-build/GAPlugin,neilrackett/cordova-plugin-ga,khalidb91/GAPlugin