[GenericDepthPlugin] Compatibility/AR fixes + preliminary DOF

* More games supported (RE4, Batman AC, Mirror Edge... though with a few shadow issues around the character for the latter)
* Better strategy for detecting the game depthstencil to replace (code is a bit awkward but it works)
* Fixes for 16.10 users like me where SSAO was misaligned when games still output 16:9 RT/DSS (like Dark Souls 2 or RE Revelations) using your very useful aspectQuad() function. I'm now using a separate pass to handle the AR correction because I was getting [these](http://abload.de/img/screenshot_2014-10-21b6qex.png) weird scanlines before :/
* Preliminary support for DOF. Everything is done on the CPU side. All it needs is some more work on the dof shader to read properly the depth from the injected depth texture
* Better defaults for SAO. This is how Dark Souls 2 [should look](http://abload.de/img/screenshot_2014-10-24k8oyp.png) with the GenericDepthPlugin and SAO default settings (9 samples, radius 2.4...)
* Dark Souls 2 Plugin duly tested and still functioning properly