Make positioning slim side more flexible

Rethink the logic in terms of how I actually want it to work and write
it with that in mind. Uses proper numbers (instead of guesses) for
taskbar.

Now it figures out what the left bound of the workarea is and positions
relative to that.
Change GetScreen* to GetDesktop*

The numbers returned are essentially the bounds of the desktop. They
account for the taskbar location, so they are not the full bounds of the
screen.
Make autohotkey scripts executable with :make

Don't need to chmod them since it's windows, just set makeprg when they
load. Remove useless bit from modeline since that's not allowed.

Oh, and update Win+v to vim 7.4. Clearly I don't use it.
Make SlimRight take inputs instead of hardcoding

Allows me to define multiple functions for different sized games instead
of hard coding these values directly inside SlimRight.

Rename SlimRight to FitToRightOfWin and add new SlimBesideGame that
has the same behavior as old SlimRight.
Add cinoption for # as comments

Not sure why this isn't already set.
Add FitBelowWin and SlimBelowGame

FitBelowWin is like FitToRightOfWin, but it puts the window below my
game.