Adding warning message for bad choice column headers and removing them.
Adding support for generating xforms with flat instances for ODK Tables
Autogenerating empty group names.
Merge pull request #34 from UW-ICTD/develop

Merging modilabs + added warnings + flat instance option
Removing troublesome print statement
fixing duplicate col header warnings + disabling nameless groups for now
Merge branch 'master' of github.com:UW-ICTD/pyxform into develop
updating readme
More readme updates
Quick fix for instance flattening code
Updating test for instance flattening bug
Merge branch 'master' of github.com:UW-ICTD/pyxform into develop
Removing group binds from flattened forms.
Adding support for required_message and no_app_error_string
version bump
Update to ODK Validate 1.4
Update to 'ODK Validate 1.4 for ODK Collect v1.4 and older.jar'
Adding support for required_message and no_app_error_string on xform to survey object