TEIIDDES-1910: Fix validation issues with WSDL property pages

* WSSoapPropertyPage
 * Display the EndPointName and the BindingType properties since they are
   necessary for the WSDL SOAP wizard
 * When replacing the existing properties, rather than creating a new
   Properties object, clone the original. This allows overwriting of
   existing property values but avoid wiping out other values
 * Ensure the EndPointName and BindingType properties are included in the
   connection profile properties

* TeiidDataSourceFactory
 * Avoid exceptions if the connection profile returned by the model
   resource is invalid

* WsdlDefinitionPage
* ImportManagerValidator
* WsdlOperationsPanel
 * Improves the WSDL importer's validation and error message display if the
   connection profile is invalid
 * Specifically validate the connection profile properties to ensure the
   minimum required properties are present
 * If the connection profile is invalid then set the wizard page status
   appropriately
 * If the wsdlModel is not parseable (unconnected) or the port name is
   missing then refresh the operations panel to display nothing

* ModelImpl
 * Avoids assuming the port name will return a sensible operations map

* WidgetUtil
 * Provides a method for setting the text value of a Text widget that
   ensures the value is not null since this throws an SWT exception
Merge pull request #250 from phantomjinx/master

TEIIDDES-1910: Fix validation issues with WSDL property pages