Merge pull request #32 from YetiForceCompany/developer

Developer
Improvement sending invitations at your calendar using iCal
Merge branch 'master' of github.com:YetiForceCompany/YetiForceCRM
Add a template email to calendar invitations
Merge pull request #33 from YetiForceCompany/developer

Changed a function that casued 503 error in a detail view.
Add loading ISC invitations to calendar
Merge branch 'master' of https://github.com/YetiForceCompany/YetiForceCRM into developer
Improvement of migration mechanisms