feat(builtin/basic): add UnfoldExists and neq

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(kernel/expr): compress application serialization

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(kernel/object): compact object serialization kind ids

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(util/object_serializer): add methods write_core and read_core that allows to pack information in the byte used to indicate whether an object is already in the cache or not

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
chore(builtin/basic): remove unnecessary parentheses

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