Add a vimmerge script to do perforce merges

I set this as my Merge tool and now I can do merges in vim!
Add Quick wrap toggle

I've been turning wrap on and off quickly recently. Make it easier.
Add map to search within visual block

%V lets you search within the last visual block selection.
Switch from powerline to airline

I've had a lot of slowdown recently. I did a long trial to see if
switching to airline improves performance. I haven't noticed any
slowdowns since, so I'm switching to airline.
Do not use whitespace checks in airline

I edit too many files that I can't clean up, so I don't generally want
whitespace checks enabled.
add sanity theme for airline
sub: bugfix for airline to show qf title
sub: don't show inactive ctrlp modes in airline

Use my change to hide this confusing extra text.
Don't change ctrlp status if using airline

Just like powerline, airline overrides my setting, so don't bother
setting it.
Add my current autohotkey setup

I use this mostly for window management: closing, minimizing,
maximizing, and moving.

To install, create a shortcut in Startup to:
c:\david\settings\daveconfig\win\autohotkey\AutoHotkey.ahk
Disable nofork; doesn't seem necessary

As far as I can tell, it's not needed.
Add QFilter command to modify quickfix

Sometimes I have entries in the quickfix that I want to ignore. This is
a simple way to remove them.

Maybe can replace with https://github.com/jceb/vim-editqf which lets you
edit the quickfix just like normal text.