ps1 and ps2 emulator mods

Hi all, I am providing some emulator mods for ps1_emu, ps1_netemu, ps2_emu, ps2_gxemu, and ps2_netemu, all courtesy of kozarovv. A variety of features have been introduced, such as new config commands for ps2_netemu, external config support for ps2_gxemu, GTE widescreen support for ps1_emu and...