Prompt opens asking user to input relative file path, which on hitting
OK will attempt to open. Triggered with CTRL+o shortcut, which is also
added to help screen. Also clarified CTRL+g and noted it's anywhere, not
elsewhere.
Shortcuts added for duplicate line & remove line.
Also moved all file manager and more general shortcuts to the right,
giving editing shortcuts more room. Make all alpha keys lowercase and
clarified a couple of areas such as left click instead of just click.
All server variables such as codeMirrorDir, visibleTabs etc now in
$ICEcoder array
This is so we have a single object to contain all settings, just like
the JS equivalent
