Fix TestSkipped importing with unittest2.

Fixes compat with 'raise TestSkipped' when running on Python2.6 with
unittest2 - bug #1190951.
Disable hiding internal frames within user frames.

Per bug 1188420 this currently completely hides important context.
Prepare for 0.9.32
Opening 0.9.33 for development
Fix a KeysEqual bug.

See https://bugs.launchpad.net/testtools/+bug/1177217 for details.