Invitation model
Merge branch 'merge-without-activation-changes' into invites
Simple user creation, no invite emails yet
Default send_email to False, fixing tests that assumed otherwise
Ensure invitations are created in the appropriate locations
Merge branch 'merge-without-activation-changes' into invites

Conflicts:
	mysearches/forms.py
Reference model in factory by string rather than import
Merge branch 'master' into invites
Merge pull request #910 from DirectEmployers/invites

Create invitations for MyJobs accounts [PD-542]