fix #7312: fix immediately saving of preference changes

ref #7268 Implement own extension point for preferences

Conflicts:¶

eu.etaxonomy.taxeditor.workbench/fragment.e4xmi¶

ref #6190 removing svn property place holder in first line of code - java files

fix #6215: check for datasource when opening preferencepage

#5301 Fix null session issues, Add remoting session for feature tree editor

Change null session to singleton with no owner

#5122 Implement Null Entity Session and integrate it in required preference pages