Provide options.checkKeys support for LocalCollection's (Minimongo)

[hwillson]

Migrated from: meteor/meteor#8386

[mitar]

I still have a question how can this potentially work. If you allow insertion of a document with dots in the filename, like:

{
  'update.field.with.dots': 'bar',
  'update': {
    'field.with.dots': 'baz'
  }
}

If I do: {$set: {'update.field.with.dots': 'foobar'}}, how does MongoDB knows what to update?

[TimKoehler]

Important feature. Any progress yet?