v1.2.1

This release doesn't contain any big features, but lots of small improvements
and bug fixes.

New Features

Overlay Badge

Since "Fork me on GitHub" badges are so popular these days I decided to join in
on the hype. The -ds <str> switch can now be used to place a ribbon with
arbitrary text over the top right corner of the editor. It was a cheap change
for a cheap joke but maybe somebody will get something useful out of this.

Keybinds Menu

Another step towards increasing user-friendliness. Press F1 to view all key
bindings.

Other Changes

• Lots of new language definitions, thanks to @ararslan for providing the
  majority of them =)
• Renamed the executable to wsed. I've meant to do this from the very
  beginning but I haven't gotten around to looking it up until now.
• Atomic saves can now be disabled using -fa.
• The config directory traversal is now deep, i.e. files in subdirectories will
  now also be read.
• Adjusted the colour scheme of unprintable characters to be a little bit less
  obnoxious.
• wsedit now prompts before opening large files, as the initial cache building
  can take up to some minutes for bigger logs.
• The status box (bottom left corner) is now coloured.
• Switched to stack lts-8.0, making use of the new ghc 8.0.2.
• Escape sequences can now be longer than a single character.
• Retroactively added CHANGES.md to mirror the GitHub releases page.

Fixes

• Fixed an error where the cursor position detection for bracket highlighting
  was off by one character.
• Saving a file with jump marks present no longer crashes the editor.
• Fixed -ad not picking up subdirectory rules correctly.
• The viewport is now limited to the text's bounds, at least one row / column
  must be displayed at any time.
• More performance tweaking.
• ssh was sometimes breaking the clipboard, it should no longer do that.
• The clipboard file (if present) is no longer world-readable by default.