aero: Implement as a plugin

[nmlgc]

All this patch does is to change the parameter of all calls to DwmEnableComposition() from 0 to 1. This is exactly the sort of thing that can quickly be implemented using thcrap's function detour API and then automatically work for every build of every existing and possibly future Touhou game.

This needs a plug-in system (thpatch/thcrap#48) because Aero support should stay an optional feature. Apparently, there are problems with certain graphics drivers that lead to crashes when Aero is not disabled, which is probably why ZUN chose to do it in the first place.

Marking as minor though, since current versions of Windows don't have Aero anymore.