Allow QSelectSection to work with subclasses of QSelectItemElement.

Changed the ```isMemberOfClass:``` call in the ```addElement:``` method
to ```isKindOfClass:``` to allow for proper subclassing of
QSelectItemElement.

I ran into this bug wondering why my ```AttributedSelectItemElement```
subclass of ```QSelectItemElement```
subclass didn't seem to work as expected.
fixed issue with boolean switch in sample code not able to execute selector specified.
fixed so subforms have correct controller name set
Remove redundant method declaration
Added trim policy to JSON
Merge pull request #528 from charlesbedrosian/master

fixes to method not found errors on QuickReportController in sample code
Merge pull request #527 from bartvandendriessche/enhancement/allow_qselectsection_to_work_with_qselectitemelement_subclass

Allow QSelectSection to work with subclasses of QSelectItemElement.
Merge pull request #533 from Igotit/master

Remove redundant method declaration