Most plugins are not used anymore; some (eg. pathogen) have been
replaced by native Vim features, some will be replaced using new Vim's
plugin system.

On Fedora, commonmark is from nodejs-commonmark, which is long-term
broken.

Not using devel anymore; master will suffice.

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.

Checking on sorted versions of these files, it looks like x-t just added
couple of new config keys.

"activation" is eg. when opening new tab/window using CLI and a
window-managing app such as Firefox.

This has been bugging me for ages with qutebrowser, which (possibly by
bug) activates previous window even in non-tab mode, preventing new
window to appear in intuitive order within current container.

Make it easier to realize which window raised it.

For things like sudden perf issues

For things like trying to catch a tram...

    https://www.youtube.com/watch?v=XA2WjJbmmoM

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.