Delete .so files prior to copying over new .so files

[NDietrich]

Currently, PP does not delete the contents of the .so folder prior to copying over new .so files from the ruleset (via the temp folder).
The contents of the .so directory should be deleted (only .so files I think) prior to copy.
Question: should we only delete the file names we're copying, or all .so files? I can see both ways having benefits (removing cruft vs. deleting files that the user installed themselves from another location).

[NDietrich]

note: the shutil().copy method we're using overwrites target files if they exist.