Consider replacing logic in find_all_file_versions() with multi-line regex

[JElchison]

It may be possible to replace the complicated logic in find_all_file_versions() with an expanded histRegex.

Consider:

• re.MULTILINE(specifically, $ and ^ will match beginnings/ends of lines)
  • ^ will also match end of entire buffer (useful for grabbing last comment, if present)
• re.findall() (specifically, its non-overlapping quality)
• capitalizing on Comments - text, which isn't currently in histRegex
• may need to find some way to lump end of comment into previous match
  • possibly split buffer into pieces, using MatchObject.start() as separation point