Squashed 'qa/rpc-tests/python-bitcoinrpc/' content from commit e484743

git-subtree-dir: qa/rpc-tests/python-bitcoinrpc
git-subtree-split: e48474322de165212c5aa29574297e78b09df8d6
Python-based regression tests

skeleton.py : a do-nothing test skeleton
listtransactions.py : start of regression test for listtransactions call
Merge pull request #3763 from gavinandresen/regression_tests

Python-based regression tests