Fixed rendering checkboxes: alignment of multicheckboxes was still buggy - multi in vertical and horizontal are ok now. The labels too.
AbstractBuildForm.php, Constants.php: The checkbox is now only wrapped in a <label> element in ALIGN_VERTICAL Mode. This is identical to the radio.

Fixed rendering of ' checkbox'. formelement.parameter['orientation'] removed (replace by formelement.maxLength)
UserManual/index.rst: Doc updated for checkbox/maxlength.
AbstractBuildForm.php, Constants.php: class 'checkbox' and 'checkbox-inline' always rendered. Insert <br> where necessary.

Changed Makefile: please do

  rm -f .bowerpackages .doc_plantuml .npmpackages \
   .phpdocinstall .plantuml .support .support_plantuml
  rm -rf doc
  make bootstrap

AbstractBuildForm.php: Class 'radio' or 'radio-inline' assigned to each individual radio element. After formelement['maxlength'] elements, a <br> is rendered.

QfqForm.js: support `required` configuration attribute.

Recode: fromelement.mode='readonly' new implemented on client, by using CSS attribute 'disabled'. The HTML atrribute 'readonly' is fine for pure 'input' elements, but does not work sufficient for 'select', 'checkbox', 'radio'. Also, the label (left of input) and note (right of input) are now grayed out if set to 'disable'.
FillStoreForm.php, Save.php: strings replaced by constants. New central function getfeMode() used by getJsonFeMode() and getAttributeFeMode()

Support for `data-hidden` and `data-disabled` attributes, which are used to initially configure form elements.