Mod 20	6 Apr 79
-- Changed 12-pitch DTC terminals to still space 1/6 inch (instead
   of 1/8 inch), unless the 'x' register is non-zero -- doable with
   the -rx1 option on the nroff command line.

Mod 19	28 Mar 79
-- Had .ep do a .rs, to avoid occasional problems (like with
   .+c (again).
-- Added the 'X' register: if non-zero on startup on a 12-pitch
   terminal, it outputs 6 LPI instead of 8 LPI.

Mod 18	26 Mar 79
-- Had .+c reset indent, to solve problems of prelim material
   after a .ip (as with references)

Mod 17	19 Mar 79
-- Fixed a bug in .++ which caused it to renumber pages incorrectly,
   the result of nroff starting a new page immediately upon reaching
   the end of the previous page (damn!).

Mod 16	8 Mar 79
-- Fixed a bug in .++ which caused it to change page number formats
   before forcing out the page.
-- Changed tmac.e so that extra '.so's to the package will next to
   'null.me'.
-- Changed .sh so that a title of "_" will cause section depth change
   side-effects only (base indent will remain the same, and no output
   will occur).

Mod 15a	7 Mar 79
-- Fixed a bug in Mod 15 which caused .ip's to fail.

Mod 15	2 Mar 79
-- Changed .@p to do paragraph indents normally in keeps, which
   will override the indent parameter in keeps with paragraph
   forms in them (use .ba to fix this).

Mod 14	23 Feb 79
-- Fixed .ip so it would hyphenate correctly.

Mod 13	16 Feb 79
-- Added .rs before eqn title output to fix vertical centering
   problem.

Mod 12	15 Feb 79
-- Changed NROFF bold font to be regular .ul (.cu is a pain).
-- Changed .sh to output regular spaces instead of unpaddable
   spaces.
-- Fixed bug in .1c with bad line length (didn't reset \n($l).

Mod 11	13 Feb 79
-- Added hook to .$c to call .$C (for index entries or whatever).

Mod 10	12 Feb 79
-- Had .xp print in current environment and not reset to single
   spacing, to allow more control over output format.

Mod 9	26 Dec 78
-- Fixed yet another problem with equation spacing.

Mod 8	18 Dec 78
-- Fixed .@q to solve a problem with \n(dn getting lost on
   equations at top of page.

Mod 7	11 Dec 78
-- Had .@q (equation output) move to end of equation after
   equation output (eqn doesn't seem to space quite right).

Mod 6	27 Nov 78
-- Fixed the umlaut on DTC output to be prettier.

Mod 5	5 Nov 78
-- Fixed a bug with the second parameter to .ip.

Mod 4	2 Nov 78
-- Added .uh command (unnumbered heading).
-- Changed .$p and .sh accordingly.

Mod 3	2 Oct 78
-- Fixed .ne command in .$p (print section headings).

Mod 2	25 Sep 78
-- Changed .np to use () instead of [].

Mod 1	12 Sep 78
-- Fixed footnote fudge factor (curse NROFF!!)
-- Put "needs" on .(z, .)z.

Mod 0	11 Sep 78