Add egw groupcal webinterface screenshots

calendar/groupware.markdown

@@ -51,8 +51,14 @@ Example workflow:
 
 - Grant access to others (in the personal or in the group calendar)
 - Others can then access the calendars via webinterface
+
+[[!img /media/groupware/egw_1.png alt="D-PHYS Groupware" size="200x"]]
+
 - For adding entries to other calendars instead of the personal one, you
 need to use the 1 day or 7 day view
+
+[[!img /media/groupware/egw_2.png alt="D-PHYS Groupware" size="450x"]]
+
 - Each user then needs to configure which calendars to sync to clients
 via CalDAV (by default only the own personal calendar is synced)
 - Sync calendar with applications (each user authenticates using their