Open files in binary mode
Stop erasing binder types in executor
Require that arguments to case blocks be reduced

Fixes #1474.
Better errors from executor
Support the RTS function idris_time in executor
More informative provider error
Merge pull request #1475 from david-christiansen/testing-postulates-work

Executor improvements
Add completion support for newer command arg types

Fixes #1477.
Merge pull request #1479 from david-christiansen/issue/1477

Add completion support for newer command arg types