Fix gamma issues in light render

indra/llrender/llrender.cpp

...wview/app_settings/shaders/class1/deferred/impostorF.glsl

...wview/app_settings/shaders/class1/deferred/materialF.glsl

...pp_settings/shaders/class1/deferred/multiPointLightF.glsl

...app_settings/shaders/class1/deferred/multiSpotLightF.glsl

...iew/app_settings/shaders/class1/deferred/pointLightF.glsl

...ew/app_settings/shaders/class1/deferred/softenLightF.glsl

...settings/shaders/class1/interface/twotexturecompareF.glsl

...app_settings/shaders/class2/deferred/multiSpotLightF.glsl

...ew/app_settings/shaders/class2/deferred/softenLightF.glsl

...view/app_settings/shaders/class2/deferred/spotLightF.glsl