Improve the PreparedRequest docs.
second commit : Fixed #1623. Added 'MD5-sess' algorithm to HTTPDigestAuth
Modified the tests so that they use py.test convention
close files in setup.py

otherwise python3.4 warns
Fix for AppEngine
Merge pull request #1708 from alex/patch-2

close files in setup.py
Merge pull request #1707 from canibanoglu/tests

Modified the tests so that they use py.test convention
Merge pull request #1706 from daftshady/dev2

restoring pull request fixing #1623
Merge pull request #1702 from Lukasa/docs_n_stuff

Improve the PreparedRequest docs.
fix @lukasa's lack of taste :)

#1702
Merge remote-tracking branch 'origin/master'
further cleanup examples
Merge pull request #1709 from samuelhug/test-branch

Fix for AppEngine