Add preliminary travis support.
Try py.test instead of trial; try 2.5.
Drop python 2.5; install parsley for running tests.
Oops; py.test takes filenames, not module names.
Swap coveralls implementations; add 2.6 compat.
It's spelled 'coveralls', not 'coveralls-python'.
Remove py.test dependency; restore python 2.6 support.
Retry trial for travis.