printcap and filters for TI OmniLaser 2108 and 2115

[Ed Cain]

These laserprinters are nice, supporting several printer emulations in
addition to PostScript.  Some other emulated printers include Diablo 630,
TI 855, and HP LaserJet+. The PostScript interpreter includes a command to
switch over to other emulations, and of course you get back to PostScript
with an escape sequence.

I've fiddled with printcaps and filters for some of the emulated printer
modes, and before investing too much more time I thought I'd check and see
if someone else has already developed a pleasing set of printcap entries,
prologues, and filters for these models.

Ed Cain