Don't use `+` for space in `objectToQuery`.

Apparently some ArcGIS servers are non-spec-compliant and don't properly handle `+` as space.

Fixes #2192
Add comment about the workaround.
Merge pull request #2193 from AnalyticalGraphicsInc/objectToQueryWorkaround

Don't use `+` for space in `objectToQuery`.
Merge remote-tracking branch 'upstream/master' into cache-models

Conflicts:
	Source/Core/objectToQuery.js
	Specs/Core/objectToQuerySpec.js