PostRetweet function implements retweet API

Added a PostRetweet function which implements the retweet API.

https://dev.twitter.com/docs/api/1/post/statuses/retweet/%3Aid

Also works with Twitter API v1.1.
Merge pull request #46 from sebastianw/retweet

PostRetweet function implements retweet API
Use default python version

Remove specific python version and use /usr/bin/env to determine
executable.
Merge branch 'master' into hashbang
Merge pull request #47 from sebastianw/hashbang

Use default python version
Change API base URL to version 1.1
Update GetSearch to API 1.1

https://dev.twitter.com/docs/api/1.1/get/search/tweets
VIM modeline for two-space indents
Update GetUserTimeline to API 1.1

https://dev.twitter.com/docs/api/1.1/get/statuses/user_timeline
Updated twitter_test.py to API 1.1

Updated test URLs to API 1.1 and changed syntax for GetUserTimeline
VIM modeline for two-space indents

VIM modeline for twitter_test.py
Updated Api.Status class to API 1.1

Added new fields from

https://dev.twitter.com/docs/platform-objects/tweets

There are a few older fields which are not documented but still used by
the Twitter API so no fields were removed.
adjusted PostUpdate() for api v1.1
PostRetweet updated for api v1.1
adjust GetUserRetweets for api v1.1
NOTE this technically doesn't exist in the v1.1 api as it's now
a special case of GetUserTimeline -- we may just remove this in
the final push
adjust GetReplies for api v1.1
NOTE we may deprecate this as it is now nothing but a special case
of GetUserTimeline
simple typo fix
adjusted GetRetweets for api v1.1
Merge branch 'master' of github.com:bear/python-twitter into api_v1.1

Conflicts:
	twitter.py
adjusted GetFriends for api v1.1