Fix documentation

Some HTML elements were incorrect and a missing word.
Fix nottyitalic

If it is unfortunate to mix colors and italics because the terminal
can't properly display it, nottyitalic shall allow to see (at least)
the colors on the screen. This works if the terminal implements what
Elvis uses to display italic. If the terminal, however, doesn't
implement what Elvis uses to display italic, underlining is selected
to represent italics - which gives a different result.

The behaviour for nottyitalic should be identical for both types of
terminals.

So move up the condition checking for nottyitalic so that COLOR_ITALIC
can get removed first of all - before it possibly will be replaced by
COLOR_UNDERLINED.
Fix o_directory handling for the Unix port

The directory for temporary files gets set unconditionally from
sessionpath which is unpreferable. The environment variable TMPDIR
usually represents a pathname of a directory for temporary files.

Use OSDIRECTORY in order to get TMPDIR. (Elvis already pays regard to
TMP, but this isn't used commonly by Unix.)

Since OSDIRECTORY isn't defined so far, it won't harm using it.
If TMPDIR isn't set, nothing changes from the current behaviour.
Fix man pages

It should be minus signs, not hyphens.
Fix (elv)fmt man page

The formatting caused the text to not be displayed.
Arrange scripts alphabetically in documentation
Fix 'cb' script and supplement its documentation

1) cbload didn't return to buffer if analyzing file content failed
2) table header underlining was too short
3) numerical argument(s) to cbshow didn't work
4) empty cut buffers caused error "line called with bad arguments"
5) pure numerical content wasn't displayed correctly

Since :cbsave and :cbload have constraints, mention it in the
documentation.
Improve handling of internal cut buffers with marks

Usually the nine internal "1 to "9 cut buffers get shifted so that the
oldest one gets lost and the last nine onces are still accessible.
Because cut buffers with marks can't be deleted, a problem arises if all
of them have marks.

By now the first cut buffer "1 will always be reused then (which
according to a comment in the source file is save), but the user will
always lose their last but one buffer information while "2 to "9 keep
sticking at their respective content.

So, even if all cut buffers have marks they still should shift as they
would do without marks. In order to accomplish that, "9 will temporarily
be renamed "~ and after the shifting renamed "1. That way, the reused
one is actually "9 while "1 to "8 have shifted nicely.
Add bangs missing in the documentation
Remove probable leftover in sentence from the documentation
Be more verbose on the ternary like operator in the documentation