Fix stack overflow exception when handing circular schema references
* ImportWsdlSchemaHandler * Current implementation has a depth setting of 1000, which is too high for some systems. * Reduces depth threshold to 750 * Make a JVM system property for increasing this threshold should it be required. * Should the threshold be set too high, catch the stackoverflow exception, issue a warning and exit
* General housekeeping of making fields private and create a getter for those to be accessed externally.
TEIIDDES-1396 - Circular references in WSDL schemas can still result in stack overflow errors