This reverts commit 75f09a80.

Prevent None being converted to string and causing confirmation pop-up

Fixing the action decorator import statement

fixed problem with wtf.FileField not getting updated with request.files data upon instantiation of Form

Fix typo in docs

Add ability to annotate field with help text

As indicated in WTForms documentation, fields have a description, which is
typically used for help text [1].

Also, in Twitter Bootstrap, help text are supported by `p.help-block` element
[2].

[1] http://wtforms.simplecodes.com/docs/1.0.1/fields.html#wtforms.fields.Field.__init__
[2] http://twitter.github.com/bootstrap/base-css.html#forms

I guess `form_columns` docstring was copy-pasted from `list_columns` and the
occurrence of the identifier wasn't replaced.