Replace JsonNode.with() with JsonNode.withObject()

[cowtowncoder]

Currently JsonNode has 2 related methods:

• with(String) which is to be called on JSON Object node, and find-or-create a JSON Object node of given property
• withArray(String) which is to be called on JSON Object, and find-or-create a JSON Array node of given property

Now that we are about to implement #1980, it looks like with() is unnecessarily ambiguous and it'd be better to have slightly longer but more meaningful name of withObject(). This can be done by adding the new method and deprecating old one; old method needs to be left for the remainder of 2.x series but then dropped from 3.0.