This introduces a skip_if module that can be used by tests to
determine when they should be skipped due to the environment.
Some tests have been split in order to have finer grained skip
control.
Tests which don't work with small ints are suffixed with _intbig.py. Some
of these may still work with long long ints and need to be reclassified
later.
Dan Halbert
Matt Wozniski
Scott Shawcroft
Damien George
Paul Sokolovsky