code: private CmsResource getResource(CmsObject cms, String resourcename) {
  
          return getResource(cms, resourcename, CmsResourceFilter.DEFAULT);
      }
docs: Trys to read the resourcename after removing the file extension and return the
  resource if the type id is correct.<p>
  
  @param cms the initialized CmsObject
  @param resourcename the name of the resource to read
  
  @return the resource or null if not found