give OpenLayers.Map a resolutions property

please review

patch looks awesome. two things:

• //OPTIONS - I deliberately set that at two spaces indented so that it breaks with the vertical line of all the properties to denote a new section. If you hate that, make it four. But otherwise pretty please leave it as is.

• The 'options' property in Layer.js -- I dont think that guy should be public. it's only there for the purpose of being able to clone layers, and ideally the user should not touch it. Rather, if the user wishes to add an option post-hoc, he/she should use the addOptions() method.

... which actually brings to light the idea that the users really *shouldn't* be setting *any* of those options directly on the layer but should rather be using addOptions(), otherwise their layers will not be correctly cloned. But hey. If you just set options to Property instead of APIProperty, I think it's good enough.

comments and resolutions property on Map

excellent. please commit.

resolved with r3568