Ensure that '.util.chunks()' closes stream after exhausting it.

Suppresses resource warning in Py3k.
Add 'before_render' hook for propertysheets.

Allow them to mutate the form before rendering it.
Revert "Ensure that '.util.chunks()' closes stream after exhausting it."

We rely on being able to use the stream after chunking it.

This reverts commit 5ec3f26de3f5b710fc81e8e2ceba29c0ffbbb560.
catalog narrative documentation: fix indent
evolution.rst: markup fix
api.txt: Don't show inherited member properties of Catalog (Folder stuff)

cc @mcdonc to double check if there is a reason to have that
ContentRegistry.find: mention pyramid.traversal.find_interface exists
docs: fix some typos
files not folders
Merge pull request #180 from mgrbyte/patch-1

files not folders
docs: update broken snippet, add doc reference
Merge branch 'master' into i18n
coverage, dont depend on babel at runtime; instead use abbreviation of locale name