enable support for alternative data compression

which can be supplied to the client.
set default time to 0

because unless i want it to expire, keys should stay in my cache
fix python2.6 failure with assertRaises syntax

pass functiona and options rather than use as context
fix duplicate run of test_simple_functions

import other test module instead of single class into namespace
Merge pull request #19 from underrun/default_time_zero

set default time to 0
Merge pull request #18 from underrun/compression_options

enable support for alternative data compression
Merge pull request #21 from underrun/fix_redundant_tests

fix duplicate run of test_simple_functions
Merge remote-tracking branch 'upstream/master'