Removed DX9 and speed optimizations

[degasus]

woo...

"Then there was an unofficial DX9-Final build released"
rodolfo still maintain this "fork" as he backports some changes from master into our DX9-final branch: https://dolphin-emu.org/download/list/DX9-Final/

DJBarry004: all of your improvments was done before removing D3D9

neobrain did a lot of work for accuracy in the tev_fixes_new branch, but it isn't merged right now: https://dolphin-emu.org/download/list/tev_fixes_new/

But as I know, nobody started on the big performance optimizations. Sorry, I was too busy :-(