w32: update manifest for high DPI and Windows 8.1

Since Windows Vista, when running at 144 DPI or higher with composition
switched on, applications that don't declare themselves to be DPI aware
are stretched by the window manager, kind of like low resolution apps in
OSX.

To avoid this, declare DPI awareness in the manifest. Since mpv is
practically resolution independent this shouldn't cause any trouble. The
'True/PM' value declares per-monitor DPI awareness in Windows 8.1, so
that the mpv isn't shrunk when moved from a high DPI screen to one with
a lower DPI.

Also, avoid compatibility shims by declaring compatibility with all
Windows versions from Vista to 8.1 and add the missing uiAccess
attribute to the requestedExecutionLevel element.