This adds optional MouseFlags that can be used to adjust what is
tracked for mouse reporting (leaving the other modes to be handled
by the terminal.) This should work on all XTerm style terminals,
but on Windows we have no way to be selective here.
I have rerun gen.sh having pulled the latest tcell to include this PR:
https://github.com/gdamore/tcell/pull/325.
I am using Ubuntu 19.04 - running gen.sh changed more fields than just
those impacted by the above fix. I've removed those from this commit. (I
verified that gen.sh changed those fields I've removed without the fix
above, so it's not related). Based on TERMINALS.md, I suspect you
regenerate these typically on a Debian machine(?)
Garrett D'Amore