* All features related to POSIX environments (env vars, shell stuff) gated by feature flags
* Dependencies optional per feature flags
* new CI target for non-POSIX build
* new CI target for release binary artifact
Signed-off-by: Ava Hahn [ava@sunnypup.io](mailto:ava@sunnypup.io)
This commit contains the following:
* New data types to support full tracebacks
* New traceback data type used across stl and ast
* Updates to tests
* fixes for error messaging in sym and some stl functions
* env prints variables and functions in seperate columns
* run/stl seperation of concerns significantly better
* def doesnt store lists or lambdas in the environment
* Background task implementation
* Foreground an existing task implementation
* Documentation for both
* Refactors to signal handling, process pre-exec
