it`s more pep8 now
Time how long each request takes

Stored as attribute Response.time_taken
Use timedelta and change attribute name back to elapsed
Merge pull request #1138 from clee/master

Time each request
Merge pull request #1146 from oczkers/master

It`s more pep8 now
Move the timing work to Session.send

per @kennethreitz's request
Merge pull request #1148 from sigmavirus24/timing_switch

Move the timing work to Session.send
Make Response objects iterable.
More useful docstring.
Fix test for Py3.
Merge pull request #1143 from Lukasa/master

Response as iterator