Consistent Use of BDDMockito

Mixture of plain and BDD Mockito, sometimes in the same class.

Enforce with checkstyle.

src/checkstyle/checkstyle.xml

@@ -165,6 +165,11 @@
 			<property name="illegalPattern" value="true"/>
 			<property name="message" value="System.out or .err"/>
 		</module>
+		<module name="Regexp">
+			<property name="format" value="import.*Mockito\.(doAnswer|when|doThrow|doReturn|doCallRealMethod|doNothing);"/>
+			<property name="illegalPattern" value="true"/>
+			<property name="message" value="Please use BDDMockito"/>
+		</module>
 		<!-- Whitespace -->
 		<module name="GenericWhitespace"/>
 		<module name="MethodParamPad"/>