Fix the same issue as #81 but with nuke

This reverts commit 9f3fbd93ce.

Update config.yml

use $VISUAL environment variable for plugins

falls back to previous behavior if $VISUAL is not set ($EDITOR then vi)

nuke plugin: use $VISUAL environment variable

falls back to previous behavior if $VISUAL is not set ($EDITOR then vi)

Code named after Freddie Mercury: https://en.wikipedia.org/wiki/Freddie_Mercury

If an input stream is available, prioritize that over sessions. find/grep
syntax can be very complex and can be scripted. On the contrary, sessions
can be loaded at runtime and the persistent session can be "restored".

An interesting use case is the listing is done in picker mode from a script
and the user expects to "pick" some entries among the listed search results.

Another important change is - if the user tries to load the "last session"
explicitly by name instead of using the session option _restore_, we should
not overwrite the "last session" ("@") before loading the it.