* Enable legacy mode for export translators compatible with pre-4.0.27:
* Add compatibility mappings, so that current translators don't break if they specify minVersion lower than 4.0.27. This does introduce non-compatible changes, specifically, "version" field in legacy mode is "versionNumber" in the new format. "version" in the new format corresponds to the "version" as specified for Zotero API JSON format. New translators should expect Zotero web API JSON format and should specify minVersion 4.0.27.
* Update CSL mappings to comply with new itemToExportFormat
* CSL JSON export translator needs to be updated to be compatible with 4.0.27 to export correct CSL JSON
* Use item URI for id in CSL JSON instead of item ID
* Fix note and attachment handling in itemToCSLJSON
Implements the beginnings of unit testing infrastructure using
mocha/chai. The unit tests can be run locally using test/runtests.sh,
although this will need tweaks to run on Windows. They should also run
on commit using Travis-CI.
The unit tests themselves live in test/tests. The index.js file
specifies separate test sets, which can be run individually by calling
test/runtests.sh <testsets>. Right now there is only a single unit
test, but hopefully we'll have more soon...
