Add option to ignore nodes

[vitonsky]

Add option ignoredNodes to ignore provided nodes and its content.

[vitonsky]

I think this issue has been created for specific use case, but i do not remember the original problem, so currently we can't start work on it.

I just implemented option to ignore nodes by selector in #73

I suppose that current issue is about ignore specific nodes, so i provide some nodes array to never translate it as exceptional case. But i don't know why this may be needed for any case and why we need exactly such feature.

So this issue is postponed until the case will be found