PEP 8 api compliance

Made many API renaming from CamelCase to the pythonic camel_case.
Renamed modules according to PEP 8. Introduced a new address property
in Manager that returns the server socket bound address. Renamed
various internal variables to match PEP 8. Renames accSocket to
server_socket.  Optimised imports (faster code execution by avoiding
unnecessary lookups). Moved exceptions to a new exceptions module.

This is a first attempt to make the api compliant with PEP 8.
Preemptively bumped the version to 0.2.1 but this is not necessary