Makes a PDF (and optionally a DVI if given target dvi) from
a text file, using the letter-writing rules from the a2ltx and
abulleted2ltx scripts.
Instructions to make a new letter:
cp -a ~/src/ltxletter/tmpl ~/path/to/letters/lettername
cd ~/path/to/letters/lettername
rename template lettername template*
vim lettername{,-header}.txt
make
Optionally modify the places commented with ADJUST.
NOTE: there MUST be EXACTLY ONE text file in the build directory in order for this to work.