fixed: error if no poster/fanart selected while ...

... first scraping

- fixed: no Edit Movie window displayed on first scrape after Ember
starts
- disable OK/Cancel/Rescrape and Change Movie buttons while saving movie
details and images (closing Edit Movie window)
- info displayed while Actor Thumbs downloading
Merge pull request #38 from Dekker500/Code-Documentation

Code documentation (continued) and beginning of UnitTest framework