contextParentBean.voidLookup() to hack #8.

allows to import in root context and has single bean with this class for autowiring
it might sense to move all bs xml schema to it.

   <bean id="clinicServiceVoid"
      factory-bean="root"
      factory-method="voidLookup">
     <constructor-arg value="clinicService"/>
     <constructor-arg value="org.springframework.samples.petclinic.service.ClinicService"/>
   </bean>
Change banshun namespace prefix to 'bs' in tests...

and specify spring-context XSD version
DRY test contexts configs
Update RegistryBeanTest to use JUnit annotations
Refactor tests, remove redundant fixtures
Move tests to base package
Rename some test classes and methods
Merge pull request #11 from jirutka/refactor-tests

Basic cleanup and refactoring of tests
Replace autoproxy logic with ProxyFactoryBean in lookup()
Refactor TargetSources a little bit