Create a standalone editor widget

[wapcaplet]

Editor widgets need to be independently:

• Creatable
• Destroyable
• Movable / draggable
• Resizable
• Loadable with file contents

All of this should be possible programmatically (via Javascript function calls), and from the UI. ACE editors offer a wealth of configuration options; some of those should probably apply globally (to all my open editors), such as:

• Theme
• Keybinding (vim, emacs, other)
• Code folding
• Indent guides
• Highlight current line

Some should be per-editor, such as:

• Current language
• Line wrapping mode
• Tab settings
• Line numbers

Most of these should be per-user configurations, but some should be shared between users (most importantly, the current language for syntax highlighting; there's no sane reason to allow different users to have this set differently).