fix(kernel/formatter): print level parameters

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(library/kernel_bindings): bug in mk_app, add expr_lt tests

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(kernel): remove diff_cnstrs module

We don't need them anymore. We will drop universe cumulativity from the kernel.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(kernel): remove level constraints from definitions

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(library/kernel_bindings): remove level pair and list of level pairs from Lua API

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(library/kernel_bindings): remove level_cnstrs

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(kernel): remove convertability constraints

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(kernel/type_checker): remove method is_conv

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(kernel/converter): cleanup and remove universe cumulativity support

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