Add a version check to provide good errors on version incompatibility#59

Merged

graysonarts merged 4 commits intotableau:developmentfrom

graysonarts:58-fix

Jul 26, 2016

Commits on Jul 22, 2016

add an explicit version check to be explicit about what we support
Russell Hay
committed

Commits on Jul 25, 2016

Move xml_open to xfile
Russell Hay
committed
Updating to ignore ephemeral fields
Russell Hay
committed
scrubbing thumbnails from the new twb file
Russell Hay
committed