feat(kernel/conveter): improve support for proof irrelevant in the converter

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
chore(README.md): remove link to Lean 0.1

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(doc/lean/tutorial): typos

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