support empty plain object as value

[svsool]

more information you can find here https://jira.mongodb.org/browse/PHP-172

sometimes you need save empty plain object {} as value

$document->set('myValue', new stdClass);

result:

{
  myValue: {}
}

but now it always saved as ↓, because value casts to array

{
  myValue: []
}

[coveralls]

Coverage decreased (-0.03%) to 91.925% when pulling 11e8d02 on svsool:master into d42e2bc on sokil:master.

[svsool]

looks like I need fix some tests

[sokil]

Tests are not the main problem. There are few other:

1. Back compatibility, when code starts to save {} but on modify expects []
2. Hydrating new document object with {} in field. With your code, if you save document first time, you'v got {} in db, then you read document and this field became [], because driver do not distinguish [] and {} on read from db.

So this must be done by specifying type of field, or something like that. Then hydrated and repeatedly saved document also will have {}.

By the way, why do you need {} in db, you may omit saving this field, and modilying empty field must be correctly handled.

[svsool]

Some legacy code may require this, but I agree with you anyway

[sokil]

I.l add field type functionality snd inform you here #144

[coveralls]

Coverage decreased (-0.03%) to 91.925% when pulling 11e8d02 on svsool:master into d42e2bc on sokil:master.