Add the first real unit test:

Add the first real unit test:
  Create a doc, write it to a temp file and read it again. Tests for the easy tags: author, title, comment, license and category.
Remove all gui elements from keduvocdocument.
This means that when opening a document fails, the apps have to check for the return value of doc->open().
Added an enum for the errors.
With KEduVocDocument::errorDescription a message can be generated to display to the user.
CCMAIL: peter@peterandlinda.com

svn path=/trunk/KDE/kdeedu/libkdeedu/; revision=713642