Fixed incorrect indentation
Executable scripts 'setup.py' and 'runtests.py'
Added method to allow selected tests to be run, instead of running all.

This also removes the use of the deprecated DjangoTestSuiteRunner class
Fix for issue #225 (exception when running with ATOMIC_REQUESTS), and the same applied to deleting subtrees

All explicit transaction handling has been moved to the model layer, and
uses transaction.commit_on_success or transaction.atomic, depending on the
Django version.
Added tox.ini and instructions, for easy running of tests in multiple environments
Merged wiki.compat into wiki.core.compat
Merge pull request #241 from spookylukey/fix_transaction_management

Fix transaction management - issue #225