gsdx-ogl: add preliminary support of external shader fx
gsdx-ogl: add a gui option (linux) to select external shader

Note: of course it requires a glsl shader ;)

On windows, you can set the path on the ini file. Here an example with linux path:
shaderfx_conf = /home/gregory/playstation/emulateur/pcsx2_merge/bin/GSdx_FX_Settings.ini
shaderfx_glsl = /home/gregory/playstation/emulateur/pcsx2_merge/bin/shader.fx
gsdx-ogl: support latest fxaa version

Only tested on Nvidia, please report any issue with your driver

Note: requires GL4 GPU
gsdx-ogl: port Asmodean shader to GLSL

I only checked the default configuration (on Nvidia). Please report any issue with it.
partially revert previous commit ec1da2805cea40434b042c7c5994e987e599ec0f

It breaks windows...
Merge pull request #343 from PCSX2/shader-loading

GSdx ogl: external shader loading + FXAA
OpenGL Updates - fix effects for both D3D & OGL

I had to edit this via the GitHub editor. I finish up my changes, and for some reason the pcsx2 repository won't let me read or write to it, since the last merge. I checked my other repositories, and they're working fine. ?.?
Tabbing >.>
Update GSSettingsDlg.cpp

Just add the OGL shader ini params to the file when the user enables post-processing In the options dialog.
Rearrange to right spot (I blame github editor ;p)
Small oversight fix for "sample_texLevel"
A few last bits of cleaning before merge.
gsdx-ogl: compilation fix for old distribution
Fix Cel Shader for OpenGL.
Merge pull request #346 from 3kinox/master

Linux : GSdx AVX fix
Merge pull request #344 from Asmodean-/master

[GSdx] OpenGL PP Updates