Add options to list open files in current window

Also added menu options to set keyboard shortcuts and settings. Also
updated readme.md.
Update README.md
List skips current file.

Also variables names are now more accurate.
Enhancements: Mark current file. Mark dirty files

All the enhancements can be enabled/disabled in the Settings file.
Update README.md
Avoid default keybind conflict.\nFixed Open File List Menu
Modify key binding
Merge branch 'master' of https://github.com/drikin/OpenFileList

Conflicts:
	OpenFileList.py