added missing 'uniform' to ofxThreshold shader code
added missing 'uniform' to ofxThreshold shader code

AntonioModer/ofxFX,armadillu/ofxFX,AntonioModer/ofxFX,sewonist/ofxFX,armadillu/ofxFX,ReallyRad/ofxFX,ReallyRad/ofxFX,sewonist/ofxFX