Fixed x-compatibility, added rename functions,

- Changed chars_to_remove for non-Windows users (it was removing all /
from paths)
- Added: check whether repl_str is a key in bag_dict, if so, continue
operation
- Added path_already_exists() so that duplicate paths are appended with
a correct index (ie: '_1' or '_2'). Currently being used in
cleanse_dict(). Still working on implementing it to fix duplicate names
with ® symbols
- Added function comments