Adding in the QueryModifier class

QueryModifier adds where, group, limit and order to any query.
This is now being used in the select interview dialog.
Adding logger
Adding timeout setting for Opal

Also added a few log lines
Removing stray cout debug line
Making sure that at least one image exists in Exam::IsRatedBy
Fixing bugs in Interview::Update
Adding functionality to download images from Opal
Fixing bugs, adding in retinal images
Merge remote-tracking branch 'patrick/master'