include access-control-allow-origin='*' header in various routes needed by external frontends
added static role variables to RelPackageAuthor constructor
modified store to switch to in-memory database if environment variable "rpr.mode" is set to "unittest"
fixed LogEntry.getEntriesSince()
return null if no relation package - author found
return null if no relation package - owner found
fixed Version.remove() to null the latestVersion of the package if no version is left
Version.getByPackage()  always returns an array
- added MAX_AGE static variable to ResetToken constructor
- added equals() method for consistency with other models
added unit tests for models
added first registry tests
- fixed registry.publishPackage(): when publishing an older version for the first time this one would be assigned as the latest one. use new findLatestVersion() method now
- removed unused Package property "descriptor"
- added new method Package.prototype.findLatestVersion (returns the version object with the highest version number)
- added Version.prototype.update() method (currently doesn't persist)
added test for findLatestVersion
added test for update method
added Author.getByNameAndEmail() method (using both properties to find a package/version author
make sure to clone() recursive
extended registry unit tests (password reset methods are missing)

- various fixes and refactorings in registry and package module for easier unit testing
- registry.unpublish now expects a clean semver version string (similar to publishPackage)