Revert "Fixes #1856: The default CSS class for hint generated by `ActiveField` is changed to `help-block`"

This reverts commit 7ae4695d.

Removed error-block HTML class and related styles and used Bootstrap3 standard practice about errors instead

Fixes #1681: Added support for automatically adjusting the "for" attribute of label generated by `ActiveField::label()`

doc fixes

"Item" parameter keys are the values of the checkbox list,
while the values are the checkbox labels.

Fixes #795: do not generate form-control css class for file input as it would display an unneeded border.

punycode.js asset bundle registering moved from ActiveField to validators.

Appended newlines to every PHP document that did not have a newline as the last character in the file.