Automate specific filename changes requested by Zack

Cleans up verbose filenames - replace with simple ones that only contain specified pertinent information

Filename items in order after rename:
<State abbreviation>_<document codes>_<document type>_<date>

If the filename has a number at the end of the document codes, it is a prepayment. Prepayment filenames are given a slightly different format:
<State abbreviation>_<Prepayment #>_<document type>_<date>

All numbers besides dates are removed in either case, with the exception of prepayment numbers and occasionally a lone number indicating a connection with another file. In this relatively rare case this lone number is tacked onto the end just before the file extension.

Run FilenameChange.py or FilenameChange.exe, whichever is applicable. It will open a popup box asking for a directory. Provide the full path to a folder containing files that need their names trimmed down. Click the Rename Files button and it will do just that, then close. A log entry will be made each time listing the original filenames, the new names they were given, and any filenames that were not changed.