Mindtagger now supports items.key_columns

so the same tags.json can be used across tasks.
If key_columns is absent, it will default to row index as before.
GUI source map support for uncaught exceptions in Chrome (V8)
Mindtagger versioning and more upgrading of tags.json
Redirect to the first available task if schema is unavailable
Mindtagger note tag for free text note per item
Rearranged labeling example with a handy script