Check Python's using builtin module py_compile
Reorder definitions to match registration order
Remove redundant :next-checkers
Add tests for python-pycompile checker
Document python-pycompile checker
Update changelog and credits
Support Python 2.6 py_compile errors
[Fix #484] Merge branch '484-py-compile'

* 484-py-compile:
  Support Python 2.6 py_compile errors
  Update changelog and credits
  Document python-pycompile checker
  Add tests for python-pycompile checker
  Remove redundant :next-checkers
  Reorder definitions to match registration order
  Check Python's using builtin module py_compile