JBIDE-13538 "Interceptors already contains class" error

Added disabling checkbox 'Register in beans.xml' if type is already registered.
Added condition for wizard at finish to register type only if checkbox is not
disabled (and selected).
Added test that checks if checkbox is disabled/enabled for appropriate type names.
JBIDE-13261 Conflicting handlers for org.jboss.tools.seam.ui.find.references

Conflicting handlers error messages are fixed.
Also, extra exception processing is fixed for Search Seam References is fixed. There was a big amount of
IndexOutOfBoundsException("index must be smaller than length") error messages logged at every Search operation
because of a buggy exception handling.

	modified:   seam/plugins/org.jboss.tools.seam.ui/plugin.xml
	modified:   seam/plugins/org.jboss.tools.seam.ui/src/org/jboss/tools/seam/ui/search/SeamSearchVisitor.java