Webui: added GroupTab extension

Conflicts:
	src/webui/extjs.c

Conflicts:
	src/webui/extjs.c
Webui: added bubble extension

Conflicts:
	src/webui/extjs.c
Webui: applied grouptabpanel

Conflicts:
	src/webui/static/app/tvheadend.js
Webui: some cosmetics

Conflicts:
	src/webui/extjs.c
	src/webui/static/app/config.js
	src/webui/static/app/dvr.js