Mostly turning the crank on fixing simple warnings: arrays, for
instance, can never be nil.  A couple of pointers should have been
initialized to `nil` before being tested.

Some logic in `troff` was simplified: basically, an `if` statement had
a condition that must have always been true if that section of code
were being executed at all.

Remote whitespace at the ends of lines.
Remove blank lines from the ends of files.
Change modes on source files so that they
are not executable.

Signed-off-by: Dan Cross <cross@gajendra.net>