Adding full range of Helper API Calls

Added Helper functions to invoke various Twitter API Calls:
1) User Timeline
2) Home Timeline
3) Search Query + Search Query with geolocation
4) Post Tweet

_js/twitterAPI.js => API Calls
_js/example_twitterAPICalls.js => How to use the API Calls
twittertutorial => invokes the example_twitterAPICalls.js