Description of problem:

Some users are requesting an upgrade on logging/error messages for org.jboss.soa.esb.actions.soap.proxy.SOAPProxy class when using "classpath://" protocol for the following situations:

- I attached a test case for you to try. Just deploy the esb and it should throw "java.net.MalformedURLException: unknown protocol: classpath" Although I 

    -- The NPE is raised on this call:

      org.jboss.soa.esb.actions.soap.RemoteWsdlLoader

	~line 78
  
	else if(url.startsWith("classpath://")) {
        	originalStream = ClassUtil.getResource(url.substring(12, url.length()), getClass()).openStream();
        } 

  - NullPointerException when wsdl is not found in the classpath should have a friendlier message;

  - classpath invalid characters (eg. backslash "\") validation. 

    -- Current message: org.jboss.soa.esb.ConfigurationException: 'url' property is not a valid URI." Test case: change

How reproducible:
Easy

Steps to Reproduce:
1. Deploy the attached  project "UlkoisetYhteydet-EP-esb.esb"