[PATCH 00/20] Final round of TUI refactorings

[Tom Tromey]

This is the final set of TUI refactoring patches that I've written.
Only the final patch should change the behavior in any way.

I went back and looked, and the TUI started at 10634 LOC (as counted
by wc) before I started.  Now it is 8825 LOC -- without any loss of
functionality.  I'm pretty happy about that.  I think the code is also
cleaner and easier to understand now, too.

After this I still plan to do a bit of TUI work -- I just haven't
written anything more yet.  In particular I want to fix the resize
testing problem, and fix disassembly styling, at the very least.

Tested on x86-64 Fedora 28.

Let me know what you think.

Tom