Terminator is currently wrapped twice, which makes the python hook use a
wrapped executable name to set argv[0]. As a result, Terminator can't be
matched to its desktop entry and fails to group correctly in e.g. the GNOME app
launcher. Ensuring we only wrap the executable once solves this.
This is a mostly cosmetical commit, in the sense it doesn't change the contents
of any package, but reorganizes the overall Nixpkgs expressions.
Terminal emulators are an ubiquitous tool for any Unix user; even the beginners
are routinely familiarized to it. And, manifestly, there are many
implementations of terminal emulators out there, from those traditionally made
in C and C++ to those written in Haskell and Go.
Terminal emulators deserve more highlight. This commit does that by creating a
category for them.
