Previously, under Pythonw, a cmd window would open when rar/par was
run. I discovered the subprocess.CREATE_NO_WINDOW flag and thus moved
everything over to subprocess calls to take advantage of it.
I discovered an issue when the input path was a file, winrar was trying
to access a sibling directory (particularly $recycle.bin while on drive
root) and raising permission denied errors.
If the file is on a drive mounted to a path, it was previously
calculating the free space on the mount drive, instead of whatever
the moveto drive was.
