v0.5.1

0.5.1 is a patch release that includes several bug fixes on top of 0.5.0:

• Handle aliased aggregate expressions by @jacksonrnewhouse in #263
• Improve scheduler cleanup robustness by @mwylde in #273
• Fix pipeline cleanup by @mwylde in #274
• Fix compilation for nested json schema fields by @mwylde in #278