* Add spacy.errors module
* Update deprecation and user warnings
* Replace errors and asserts with new error message system
* Remove redundant asserts
* Fix whitespace
* Add messages for print/util.prints statements
* Fix typo
* Fix typos
* Move CLI messages to spacy.cli._messages
* Add decorator to display error code with message
An implementation like this is nice because it only modifies the string when it's retrieved from the containing class – so we don't have to worry about manipulating tracebacks etc.
* Remove unused link in spacy.about
* Update errors for invalid pipeline components
* Improve error for unknown factories
* Add displaCy warnings
* Update formatting consistency
* Move error message to spacy.errors
* Update errors and check if doc returned by component is None
In general, it's nice for models to specify spaCy as a dependency. However, this tends to cause problems in conda environments, as pip will re-install spaCy and its dependencies (especially Thinc)
On fresh install via subprocess, pip.get_installed_distributions()
won't show new model, so is_package check in link command fails.
Solution for now is to get model package path explicitly and pass it to
link command.