Add example with nested quantifiers

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Fix bug in parse_arrow

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Allow notation to be associated with arbitrary expression (instead of only constants).

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Remove verbosity.cpp, verbosity message channel should not be a global.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add interrupt method to type checker.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Remove interrupt.cpp. We changed the way we will handle interruptions in Lean.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add interrupt to normalizer. Fix tests (they were not using the basic printer).

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Use normalizer object in type checker. The idea is to make sure the interruption is propagated to normalizer.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>