Text boxes,
Intiuitive Rectangle Handling
Colors
Panning the image

QfqForm.js: When handling responses to `save`, handle `element-update` independently from `form-update`

Implemented spinning wheel (hourglass) displayed during rendering and downloading PDF.
Link.php, Report.php: New $vars[NAME_EXTRA_CONTENT_WRAP] which holds a '<button>' definition with necesary 'data-*' attributes. The Modal Dialog needs a uniq html id (derived from ttContentUid). That one is returned to Report() if there is at least one download element.