Allow `sleep` to work with float values (fixes #261)
Fixed #262: issue with an untyped yield expression
Fixed an issue with a union of a module and a class that includes it (at the metaclass level)
Spec context: store descriptions as strings
Small optimization in BufferedIO#flush
More alias specs and fixes
Added Object#itself
Renamed `radix` argument name to `base`
Fixed crystal_type_id (important for exceptions and re-raising)
Added Dockerfile to generate an automated docker image on each commit
GC_set_handle_fork