Update for Clojure 1.7-alpha2, exclude update

Clojure 1.7 introduces the update function which conflicts with the update function defined in flatland. While 1.7 only causes a warning in useful, it affects ztellman/lamina causing compilation errors. This patch excludes clojure.core/update from the namespaces that depend on map/update, and adds tests profiles for new versions of Clojure. The exclusions don't affect earlier versions of Clojure which don't come with update.

I think you may be able to remove flatland.map/update completely once you require 1.7 as a minimum version as clojure.core/update provides the same functionality.