Merge pull request #1 from 2amcode/master

iOs integration
Update plugin.xml
english comments
optional overlay param, code cleanup
Merge branch 'master' of github.com:mobimentum/phonegap-plugin-loading-spinner
Update README.md
optional args now supported
Update README.md
Merge branch 'master' of github.com:mobimentum/phonegap-plugin-loading-spinner
added overlay param