Implemented basic zoom feature.
Zoom is kept across image changes, and is currently restricted to 50%, 66% and 100%
Reimplemented ctrl + mousewheel zooming with fix for previous scroll bug
Added Hotkeys message box,
changed hotkeys for first/last page to ctrl+left/right,
changed hotkeys for next/previous page to left/right
Removed redundant lower() calls,
fixed OpenFolder,
folder params now accepted via CLI and drag & drop,
grouped common param parsing into new method