chore(kernel/inductive): cleanup code

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
chore(util/rb_tree): cleanup code

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(kernel/constraint): remove choice constraints from the kernel, the kernel does not use them, we will implement them in elaborator

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(util/trie): add value() method

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

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