test(lua): add is_sorted inductive predicate example

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
test(lua): add integer datatype test

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(library/private): add hidden_to_user_name and user_to_hidden_name functions

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(library): add simple placeholder module

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(library): add module for implementing aliases and 'using' command

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