Improving BSD-licensed text-processing tools progress report.

[Jesse Hagewood]

The first part of my project is to add more features to mdocml. This week,
I spent a lot of time looking over the code and studying roff and mandoc,
and found that there are several missing text-formatting requests in roff.
Some are listed in the roff macro structure, but call a function that
prints to standard output something like "Request not implemented" and does
nothing. Others were listed in the mdocml 1.12.1 TODO file. Here is a list
of missing requests that I will add:

.ad (adjust margins)
.na
.it
.ns (no-space mode)
.rs (no-space mode off)
.ti (temporary indent)
.ta (tab settings)
.hy (hyphenation)
.ne
.nh
.ni
.ps

I have added the requests to the proper structs in roff.c and created
skeleton functions for them. This week, I will be adding functionality for
these requests.

My project wiki:
http://wiki.freebsd.org/SummerOfCode2012/JesseHagewood

SVN repo:
https://socsvn.freebsd.org/socsvn/soc2012/jhagewood/