Add separate PLISTs for python-2.x and python-3.x, to fix build with
python-3.x.
Update to 0.8, and fix PLIST for python-3.x.

0.8
  More fixes for the App Engine support.

  Added a new feature that allows you to supply your own provider for the
  CA_CERTS file. Just create a module named ca_certs_locater that has a method
  get() that returns the file location of the CA_CERTS file.

  Lots of clean up of the code formatting to make it more consistent.
Updated www/py-httplib2 to 0.8
treat python version depended PLIST handling with standard way.