New tool: `miniwdl zip`
Creates a zip archive of a WDL source file along with all imported source files. The zip includes a manifest JSON file in the style of [Amazon Genomics CLI's](https://aws.github.io/amazon-genomics-cli/docs/concepts/workflows/#multi-file-workflows) and, optionally, default inputs for the bundled workflow. `miniwdl run` can then operate on the zip directly (or zip extracted to a directory).
miniwdl zip https://raw.githubusercontent.com/broadinstitute/viral-pipelines/master/pipes/WDL/workflows/assemble_refbased.wdl
miniwdl run assemble_refbased.wdl.zip ...
Thanks rhpvorderman for prior art in [wdl-packager](https://github.com/biowdl/wdl-packager) and subsequent discussions informing this feature's design.
New tool: `miniwdl eval`
Evaluate a bare WDL expression given on the command-line; quickly trying out expressions to be used in WDL workflows, without running the whole thing.
$ miniwdl eval 'Int x = 42' 'select_first([None, x/2])'
21
`WDL` package
* Allow infix comparison between array and nonempty array constant (541 kinow)
* Fix spurious `WDL.load()` error after a previous `WDL.load()` operation failed in the same process (549 kinow)
* Don't require task `runtime{}` entries to be String-coercible