add a test with form_for and a separate view context that causes trouble.
make test work by removing haml's #form_for implementation.
make form_for test less restrictive as rails keeps changing the rendered form.
remove FormHelper which incorrectly tries to add proper indentation. since #form_for uses #form_tag we can rely on the patched #form_tag_with_haml to indent the form correctly.
add a test for form_for that tests lack of indentation.
remove warnings by initializing HomemadeViewContext properly
HTML escape interpolated code in filters

HTML escape any interpolated code if the escape_html option is set.
Merge pull request #770 from haml/escape-filter-interpolation

HTML escape interpolated code in filters
make tests run with rails-3.2 where a size attribute had to be added to the form's input.
Merge pull request #769 from apotonick/form-for

Remove FormFor Helper
Fix test warning: ambiguous first argument
Use << to concat strings instead of +
Remove test check for Rails >= 3.2, as Haml only supports >= 3.2