OrcO merge completion tracking issue

[arthurp]

This issue exists to track all the issues that are solving remaining issues and snags in Orc with Objects.

The issues are in a set of groups:

• Documentation updates: #156, #157, #158, #160, #162, #178
• Type checker fixes.
  • Very important: #165, #170
  • Stuff for later: #167, #168
• Standard library: #161
• Usability improvements: #163, #164, #166, #169, #171, #172, #173

There are also sure to be missing issues that will need to be added later.

Initial work assignments will be as follows:

• Documentation: Arthur, Taylor
• Type checker: Arthur, Dave

[arthurp]

Close in favor of "project" board: https://github.com/orc-lang/orc/projects/2