add ability to set onVisibleChanged in definition: https://github.com/surveyjs/surveyjs/issues/408
add ability to set onVisibleChanged in definition:
https://github.com/surveyjs/surveyjs/issues/408

dmitrykurmanov/surveyjs,surveyjs/surveyjs,surveyjs/surveyjs,andrewtelnov/surveyjs,surveyjs/surveyjs,dmitrykurmanov/surveyjs,dmitrykurmanov/surveyjs,andrewtelnov/surveyjs,dmitrykurmanov/surveyjs,andrewtelnov/surveyjs,surveyjs/surveyjs