Update Maintenance.java

Implemented functionality for the 'Reset Windows' button: the button will now reset both the main and maintenance frames to their default, preferred sizes and positions.

Added few more minor clean-ups to the code formatting or comments.

Changed file format from comma delimited to tab delimited (This will throw an error if you still have the original filelist.txt file with comma delimited values in your root directory. It won't affect the final runtime, so just delete the file or ignore the error, resize the window and add a new file to overwrite.)