Add BaseForm class to soc.views.helper.forms module (work in progress). This changes...

Add BaseForm class to soc.views.helper.forms module (work in progress). This changes the way as_table function displays the form (for more information have a look into doc string). BaseForm is going to be used for all forms in Melange in future. Right now it's still missing custom form errors labels and "required" text in 3rd column, but that's added as TODO and I'm working on it.

Patch by: Pawel Solyga
Review by: to-be-reviewed