Provide support for adjusting default indent. Problem:: By

Provide support for adjusting default indent.  Problem:: By
default, man pages are output with a indent of 8 characters.
That's a lot of wasted space that might better be used --
especially in cases where the content verbatim stuff that has long
lines. Change:: Added support for customizing the roff "default
indentation value" (value of IN register)
man.indentation.default.adjust (boolean) and
man.indentation.default.value params (number, 3n by default).
Also made some adjustments to get better formatting of
sub-subsection titles even without adjusting default indentation.