FXOLAT-208,OO-425: fixed changed location of tree-node-loading class and changed return value open method within FunctionalCourseUtil. Implemented some utility methods.

OO-296: fixed wrong alias in checkUploadFileArtefactWithinBinder() and fixed missing selector in artefactExists().

OO-296, non-jira: fixed extended version of FunctionalArtefactTest and various fixes related to accelerated test cases.

non-jira, OO-348: Updated tests to use instantiated site utility classes from FunctionalUtil. Fixed unsafe method clickRadio in FunctionalUtil.java.  Implementing checkCreateSubcategory test therefore I have written createCatalogSelector and createCatalogSubcategory method.

OO-296: fixed ugly sleep which was needed after creating structural element in eportfolio. The cause was some ajax code which wasn't done as the new browser calls were executed.

OO-296: Fixed filling in tags in wizard of adding artefacts to eportfolio. Fixed functional methods to work with firefox.