Can't check for trailing byte errors in get or extract

They don't necessarily read as far as the end of the CBOR object.

Add exception for path not found.

Initial CBOR support

For now, just a stand-alone command with basic read support.  Despite
suggestions in the RFC, CBOR isn't really that tight a match for JSON, but many
other JSON libraries also support CBOR, and there may be value in tight
integration to provide CBOR as a serialization option for JSON (JSON to CBOR
and back is lossless, in contrast to the other way around).

v0.14

- Fixes for set and unset cases involving variable write traces
- Export build config for jitc integration
- Stubs c API fixes
- Unload fixes
- Arg checking modernisation

v0.14

- Fixes for set and unset cases involving variable write traces
- Export build config for jitc integration
- Stubs c API fixes
- Unload fixes
- Arg checking modernisation

Build fixes

Benchmark fixes

Exclude the jsontestsuite submodule by default

Get benchmarking basically working again

Fix unicode escape handling

TIP445 compat