0.4.0 register

[JeffFessler]

@JuliaRegistrator register()

[JuliaRegistrator]

Registration pull request created: JuliaRegistries/General/1347

After the above pull request is merged, it is recommended that a tag is created on this repository for the registered package version.

This will be done automatically if Julia TagBot is installed, or can be done manually through the github interface, or via:

git tag -a v0.4.0 -m "<description of version>" 55d1ab27746e2113a7cbbae3fd32d3a9d0efc8f5
git push origin v0.4.0