AbstractBuildForm.php: fixed broken JSON Object array

Support.php: If FE_MODE_SQL is given, overwrite the static option.
FillStoreForm.php: Evaluate loaded elements to get FE_MODE_SQL evaluated.

AbstractBuildForm.php: fixed 'checkbox' update (api/load.php) - raw values like 'yes', 'no', 'enabled', 'disabled' are not understandable by the client (delivered via JSON) and needs to be converted to true/false.

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