Mapping to turn off Vim search highlighting

Despite what I said in 3d4e109, I'm changing my mapping to just turn off
the search highlighting, rather than clearing the search entirely. It
has been pointed out to me that this will affect the search history, and
I'd rather not do that.
Map ; to : in Vim

This will save me from having to press shift when I want to enter a
command.
Add a way to change Vim windows easily

I always found it awkward to have to use <c-w> to initiate changing
windows, especially to change to a window that isn't adjacent to the
current one.