moved group_activity widget from dashboard to groups plugin
removed pushing widgets context as a widget is already in the widgets
context
always show text if there is no group selected, no need to check if can
edit widget
sanitize int for group guid
Merge pull request #5914 from jdalsem/#5909-group-activity-widget

#5909 move group activity widget to groups plugin
Merge branch 'master' of git://github.com/Elgg/Elgg.git into more-specific-list-item-classes
Update CONTRIBUTING.md
Merge branch 'master' of git://github.com/Elgg/Elgg.git into more-specific-list-item-classes
move assignment outside of if