Extract rose-tree code into a separate namespace

Also removed "-rose" and "rose-" from the function names, since
they'll be referenced externally as rose/foo.

Signed-off-by: Reid Draper <reiddraper@gmail.com>
Merge branch 'feature/rose-tree-namespace'
Merge branch 'master' into fork

Conflicts:
	src/main/clojure/clojure/test/check.clj
	src/main/clojure/clojure/test/check/generators.clj