Fixing issue #159

[emesika]

Wrong code in get_defined_custom_field_type and get_defined_custom_field_types

get_defined_custom_field_type:

 self._uri, work_item_type_id, key
 should be :
 self.project_id, work_item_type_id, key)

get_defined_custom_field_types:

 self._uri, work_item_type_id
 should be:
 self.project_id, work_item_type_id

[leelavg]

merging based on

   <element name="getDefinedCustomFieldType">
    <complexType>
     <sequence>
      <element name="projectID" type="xsd:string"/>
      <element name="typeID" type="xsd:string"/>
      <element name="key" type="xsd:string"/>
     </sequence>
    </complexType>
   </element>

<!--------------------->

   <element name="getDefinedCustomFieldTypes">
    <complexType>
     <sequence>
      <element name="projectID" type="xsd:string"/>
      <element name="typeID" type="xsd:string"/>
     </sequence>
    </complexType>
   </element>