fixed memory leak due to not deleting old frames after writing to disk
fixed memory leak due to not deleting old frames after writing to disk

thelastbaldwin/ofxVideoRecorder,fx-lange/ofxVideoRecorder,galsasson/ofxVideoRecorder,DomAmato/ofxVideoRecorder,kmichaelfox/ofxVideoRecorder,smallfly/ofxVideoRecorder,asus4/ofxVideoRecorder