Feature Request: Handle Named Glyphs from BDF

[molarmanful]

In some BDF fonts (e.g. UnifontEX), named glyphs like .notdef are stored with ENCODING -1. In the case of UnifontEX:

STARTCHAR .notdef
ENCODING -1
SWIDTH 500 0
DWIDTH 8 0
BBX 6 11 1 0
BITMAP
FC
CC
B4
B4
F4
EC
EC
FC
EC
EC
FC
ENDCHAR

However, Bits'n'Picas does not display these named glyphs, nor does it include those glyphs on export.

It would be useful to support these BDF named glyph conventions for both importing and exporting.