1.5.1
Drop support for EOL Python <= 2.6, 3.0-3.3
Add TerminalWriter.chars_on_current_line read-only property
deprecate py.std and remove all uses from the own codebase/unrelated tests
Add py.error.EBUSY to the list of possible errors when creating locks
refactor class-level registry on ForkedFunc child start/finish event to become instance based (i.e. passed into the constructor)
add missed package and switch the py imports tests to parametrize
Bump version to 1.5.1 and update CHANGELOG
move down py/impl/XYZ to py/_XYZ
finalize 1.4.27
turn py.error into a actual module, fixes #73
Revert "apply the xml newlines patch, fixes #85"
slight adjustments