measure css responsiveness and change tweets list

change the tweets list to show latest tweets at the top; add media
queries to measure the compability for different size of devices.
revised tokens queue to consider rate buckets.
added comments
added addTask API for testing
Merge branch 'master' of https://github.com/hdt91/CS3281
Merge branch 'master' of https://github.com/hdt91/CS3281, delete junk
files
Merge branch 'master' of https://github.com/hdt91/CS3281
Merge branch 'master' of https://github.com/hdt91/CS3281
added function for taking in article id at dante's request
Merge branch 'master' of github.com:hdt91/CS3281
Merge branch 'master' of github.com:hdt91/CS3281
changed tokens queue to be a singleton rather than a global variable
changed tasks to use a new function specified in views instead to access
the tokens queue.
changed views to use tokens from the tokens queue instead of the user