New approach for checking we are loading the right file#62

Merged

t8y8 merged 3 commits intotableau:developmentfrom

t8y8:bugfix-60-xml-open

Jul 27, 2016

Commits on Jul 26, 2016

Proper validation that Workbooks load 'twb(x)' and Datasources load 'tds(x)' files only
t8y8
committed
Small cleanup, move the try inside the with
t8y8
committed
Add some tests to make sure I don't break anything and cleanup a few small bits
t8y8
committed