refactor(library/tactic): simplify tactic

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(library/tactic): name convention

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
test(tests/lua): add simple tactic framework test

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
test(tests/lua): add simple tactic framework test