isModuleInstalled added to BackendModel
Changed name to isInstalledModule()

Conform functions like BackendAuthentication::isAllowedModule() and
isAllowedAction().
Removed BackendExtensionsModel::isModuleInstalled()
Replaced BackendExtensionsModel::isModuleInstalled() by BackendModel::isInstalledModule()
renamed isInstalledModule to isModuleInstalled
fixed login sql error on wrong email
Location widget address fixed
email module now supports live.com via encrypted protocol SSL/TLS
updated code after feedback
update html5 shiv
deleteThumbnails function added
beter message
Email: allow null as plain_text value.

Fixes #429.
Merge pull request #421 from gertjanmeire/login-bugfix

fixed login sql error on wrong email
Resolve conflicts.
Bugfix: use correct class
Stop code execution after a redirect.

I know this is ugly as hell, but if we don't do this the code after
this call is executed and possibly will trigger errors.

This should fix https://github.com/forkcms/forkcms/issues/444
Added missing locale
Merge branch 'update-html-shiv' of https://github.com/WouterSioen/forkcms into WouterSioen-update-html-shiv
Removed local version of the html5-shiv