If BASHUM_CTXSYM is set, show it in a different color.  This is intended
for special-purpose Bash invocations with modified environment, for example
when authentication to some remote service has been pre-set.

Finally stop using few-low-lettered globals; use proper Shellfu compliant
naming instead.

Also have separate variables for use in Bash PS*; these need extra chars
for hinting.

First, I'm not sure where I took the former icon, but it does not work
out of the bos on Fedora, so I decided to use another one rather than
try to find out.

Also when a system is accessed via SSH, it will use different
(fa-server) icon.

Silly but for now it will suffice.  Maybe one day I'll learn the magic
of systemd so that I'll be able to set this up in a less embarrassing
way.

When case is left without quotes, Vim's default syntax highlighter shows
the left bracket in strong, error-y red style (not sure why, e.g.
ShellCheck does not complain about that notation).  It seems to work
fine when quoted, though.

Separate declaration from initialization and add variable comments.

...yep, we're getting a bit naggy...

This likely breaks hostname setting when accessing via SSH, but:

 *  it's first version that is at least somehow readable,

 *  and also WE *MAY* have fixed the long-standing PITA escaping
    errors that we used to get in urxvt if BASH_COMMAND had backslashes
    in it!

 *  Remove excess comments and optional syntax (eg. EOL `;`),

 *  use non-conflict function names,

 *  simplify PS1 generation,

 *  close PROMPT_COMMAND setup into function,

Script not (yet) released, but it's s simple taskwarrior wrapper to
remind about unfinished and overdue tasks once per set period.

bash 4.2 will print literal tilde, which seems like least evil.

Re-use the case switch

The backslash was needed due to [bug on Jessie][2], but on all other
macnines I use this is printed, which is not desired.

  [1]: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=767655

On Debian Wheezy the tilde expansion is performed.  Suppress it
explicitly.

Taken from an [i3 forum answer][1] and edited to remove unnecessary info
(name@hostname and $HOME path)

  [1]: https://faq.i3wm.org/question/2481/how-to-show-cli-application-name-in-window-title/?answer=2482#post-id-2482

Now `rm -rf /var/tmp/bash-rv` would only disable the feature instead of
causing errors to be printed on each prompt.

Inclusion of "real" \033 seemed to work but confused readline when
working with long history lines

*   More intuitive file naming,
*   setup simplified,
*   setup is now in script (vs. diff file),
*   removed unnecessary exec mode.