Some work on auto-formatting features, doesn't reliably work yet.
FontDisplay: Render unrecognized <variables>.
Config file: Add regex replacement types for Font.
Move config-based text replacement to the Config class.

So that it can be called easily from anywhere.
Improve font rendering/calculating.

Now has a _fallback_ char that will be used if the char doesn't exist.
Added some checks int he formatting calculation so that it doesn't try
to set a space to newline when no space has been found since the start
or the last newline.
Mark Formatting actions BETA, remove from Toolbar
FontWindow: Show JP dimensions as magenta lines.
Font formatting now understands variables, to an extent.
Turn on/off the JP dimension lines.
Font Window settings now actually show checkmark.
Put toolbar formatting buttons back, with better layout.
Properly auto-format entries with <Feed>s.