using bitly API for url shortening and other functions

Learnt from http://www.codecademy.com/ Note: we can use this Bitly API only if we have and Valid Access_Token from bitlys

Update1: Added the lecture notes and URL SHortener Program

Update2: Added program to find the number of clicks made in the bitly link and updated the lecture notes

Update3: Updated the customized program to see the number of clicks made in last few mins.

Update4: Added a program to check he number of referrers for the link.

Update5: Added program to find the category of the webpages

Update6: Added program to use bitly's search engine to find links about anything, ranked by their current popularity.