Trunk-based development
- Support for multi-version release management
- Add new {.version: "1.x.x".} pragma for new procs in stdlib, be able to define when added and removed "1.1.0, < 2.0.0"
- Ship single package with multiple branches enabled - default selected is latest version of oldest supported branch
- Add nim --list-versions to show users what versions are available (include deprecation status)
- Add nim --set-version:1.2.0 to configure global nim.cfg or user to manually edit file
- Ensure all pre-existing v2.0 features behind version block/pragma
- Fix all "high priority" bugs, "regressions" and "showstoppers" in 1.0.0 code
- Remove all deprecated symbols and update stdlib accordingly
- Test all major libs and verify working with 1.0.0 version