Several fixes and changes

Add:
- F2 in file explorer triggers rename
- Ctrl c, v, x in file explorer
- Setting: Choose which directories the source tracker will watch (game,
root, both, none);
- Copying directories in fileexplorer now works

Change:
- Ignored files are defined through regexps now
- pasting inside the file explorer now runs through all files in
clipboard

Fix:
- Errors while copying files in file explorer won't crash CEWSP anymore.