Based on feedback that it would fit better with different portal URL
generation strategies if the test driver would follow links generated by the
portal rather than generate its own test URLs, changed test framework as
follows:

* Added "test.server.login.url" property to specify the initial portal page
* Added "test.url.strategy" property that allows selection of whether tests
  are executed through URLs generated by the driver or links generated by
  the portal
* Implemented the corresponding functionality by changing code in several
  modules