Merge pull request #126 from CruGlobal/MH-636v2

Change leaders to group leaders in group page
Don't raise an exception if a person to be texted isn't found.
Don't display blank import preview
Block unauthorized API request
Merge pull request #127 from CruGlobal/MH-649

Mh 649
Change text keyword description
Merge branch 'MH-624v2' into dev