Fix issue when using API and email fields.

This change fixes an issue where handle_email_fields() expects the data
being passed in to have passed form validation (so initial values will
be there). Rather than make the handler really ugly I made the API use
EmailUploadForm properly, passing the submitted data to it.

This does mean that the data being submitted must now use 'from_address'
instead of 'from'. I've adjusted the documentation accordingly.

Fixes #201.
Update help HTML to latest.
Revert "Fix issue when using API and email fields."

This reverts commit 0235a97d28b17b24ff8942cd751be92542ec14e1.
Fix email API field upload.

Default non-required fields to sane values. This now allows users to use
the API to upload an email as fields. Any fields which are sent which are
not supported by the class will be put into unsupported_attrs.

Strip the username and API key out of the bundle before passing to
handle_email_fields() so that they are not put in unsupported_attrs.
Fix missing doc commit.

This was incorrectly included in the revert.
Merge branch 'master' into issue_201
Merge pull request #202 from crits/issue_201

Issue 201