Add screencast functionality

Jira issue: WP-705
Update webinos/core/api/tv/lib/webinos.service_tv.vlcscreencast.js

corrected IP assignment (missing ";")
Update webinos/core/api/tv/lib/webinos.service_tv.vlcscreencast.js

Fixed incorrect instantiation of VLC
Update webinos/core/api/tv/lib/webinos.service_tv.vlcscreencast.js

Improve error message
Merge pull request #430 from mjprins/screencast

Add screencast functionality