Replace is_null with isset

To prevent php errors
Merge pull request #1740 from lmm-git/patch-2

[Form] allow template to set the onsubmit tag - check correction
Updated BlocksModule version to 3.9.0

This makes room for minor fixes in the Zikula Core 1.3.x branch for Blocks.
[Blocks] Added new versionnr 3.9.0 to Installer 

Nothin to be done for this update. This small update in version nr makes room for minor fixes in the Blocks 1.3.x branch of the Core.
Merge pull request #1741 from espaan/patch-9

Updated BlocksModule version to 3.9.0
fix scanning for psr-0/psr-4 type modules for admin capabilities. fixes #1679 Also correct some general module scan issues and make sure translation domain is loaded with correct key.
remove incorrect comment
Merge pull request #1742 from craigh/adminCapabilityFix

fix scanning for psr-0/psr-4 type modules for admin capabilities.
Install the ZikulaRoutesModule when the Core is installed.
Fixed upgrading.
Merge pull request #1746 from cmfcmf/routesmodule-install

Install the ZikulaRoutesModule when the Core is installed.
Merge pull request #1747 from cmfcmf/routesmodule-upgrading

Fixed upgrade process with the new RoutesModule
Removed old LogUtil reference, closes #1565.