Encode otherwise-unencoded glyphs in the private use area

Encode otherwise-unencoded glyphs in the private use area

There are several glyphs in Bedstead that are not encoded at standard
Unicode code points.  In most cases this is because they're font
variants of other glyphs, and in one case it's a character that's
simply not in Unicode ("oldsheqel").  These can be accessed using
OpenType features or by glyph name, but not all applications make
those available or easy to use.  Giving all the glyphs code points
makes them usable (albeit with some ugliness) in pretty much any
application.

The code points I've used are in the "Reserved for font hacks" range
in the ConScript Unicode Registry, which should minimise their chances
of colliding with other useful things.