Automate creation of tarball.

This is a squash of two commits:

- Remove unused release.sh script,
- Add create_tarball.sh script for automatic creation of tarball
  with source code
Push promise frames when checking variables
Add enum SpecialScope
Add ScopeClearSpecial
Merge pull request #830 from maciejpatucha/master

Automate creation of tarball.
In parser, do not assert on unknown promise types when parsing constraints.

Close #3194