Merge pull request #189 from edevil/master

Reduce critical section protected by global lock
Point setup.py download_url at tag tarballs
Remove download_url from setup.py

Github stopped providing download hosting, and it was
decided on the user ML that there's no need to set
download_url at all -- the normal pypi tarball will
suffice:
https://groups.google.com/forum/?fromgroups#!topic/pycassa-discuss/oQ_l_coZDFg
fix example code in Getting a ColumnFamily

the "pycassa" module is neither imported nor needed
Merge pull request #192 from termie/master

fix example code in Getting a ColumnFamily
adding column start and end to get for non-composite keys
adding column_start and column_finish to multiget
updating stubs.rst
Merge pull request #195 from david-huber/master

Add column_start and column_finish support to pycassa.contrib.stubs.ColumnFamilyStub