Miscellaneous features

[hippich]

At my project I needed more flexibility in rendering forms, but I did not want to create separate templates for each case. I added set of features which should allow easier styling without changing templates. Changes includes:

• new options for validate() function 'noSetError' to not add error messages to the screen when validating form/field
• automatically generate classes for wrapper element
• allow to specify field prefix and suffix HTML
• for 'Radios' field editor add 'selected' class to wrapping
• of selected radio button
• Tests for these new features
• Updated documentation

[hippich]

Just merged upstream and resolved couple minor conflicts for smooth merge into master branch :)