Wily

* Debug logs are always stored in a temporary local file, on the event of a crash, wily will suggest the user to upload this file to GitHub with a copy of the crash log
* Unhandled exceptions raised by the operators (normally file formatting) are now debug events not warnings
* Updated to flit 2.0 for packaging (development change, no impact to users)
* Moved source code to src/ (development change, no impact to users)

* The build process uses the metadata from Git to only scan the files that have changed for each revision. Significantly speeds up build times (25x>).
* The diff process uses multiprocessing to make it 3-4x faster to complete.
* Officially add support for Python 3.8.
* Process crashes are now captured and output on the console in the debug log.
* State index building is 10-20% faster.

* Updated radon to 4.0.0
* Added support for IPython Notebooks (enabled by default)

* [BUGFIX](https://github.com/tonybaloney/wily/issues/73) Fixed ``TypeError: unsupported operand type(s) for +: 'int' and 'dict'`` occurring when a file contains multiple functions with the same name.
Fixes [73](https://github.com/tonybaloney/wily/issues/73) by alegonz
* Updated code style to meet black requirements.

* Pinned version of radon as newer version has API changes.

* [BUGFIX] Fixed an issue where illegal/unusual filepath characters within the git history would cause the halstead harvester to crash unrecoverably. Halstead will now handle and report the error but mark the file as missing in the index (https://github.com/tonybaloney/wily/issues/64) fixed in https://github.com/tonybaloney/wily/pull/63 by abadger.