Add support for the placeholder attribute for input fields.
Merge pull request #121 from hvelarde/master

Thanks!
version 1.7.16: mailer adapter looks for data grid fields that contain new File columns and includes those files as attachments
Merge pull request #120 from thet/placeholder-support

placeholder support
Merge branch 'master' of git://github.com/tkimnguyen/Products.PloneFormGen into tkimnguyen-master
Merge branch 'tkimnguyen-master'
Refine changes list
Preparing release 1.7.16
Back to development: 1.7.17
Update bootstrap.py