* Replace time.clock() calls with time.perf_counter(), as [time.clock is deprecated since python 3.3](https://docs.python.org/3/library/time.htmltime.clock) and doesn't provide consistent behavior across different platforms.
* Replace _ontimeout_ with _function_, and _params_ with _args_ and _kwargs_, to match the `threading.Timer` API.
_ontimeout_ and _params_ are deprecated and will be removed in v0.3.
* Added lots of code comments to better explain how the module works.
* More detailed README