QfqForm.js: support `required` configuration attribute.

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

Preview commit for field validation using bootstrap-validator. Do a `make boostrap && grunt` after merge

Form.js: Textarea also get input and paste event listener in order to fire upon changes immediately.

Removed global EventEmitter. Added local EventEmitter to Object really needing it. Alert.js now uses EventEmitter.

 * use anonymous functions for ajax error displays
 * expect response from server to file upload to have `status` and `message` attributes
 * replaced occurrences of `QfqNS` by `n` in order to support different namespace names.

qfq-bs.css.less: Tweaked less. Added new class for spinner. Changed display type of input[type=file].
FileUpload.js: every callback will be called with the originating file input element as first parameter.
QfqForm.js: Add spinner on upload.

tablesorter.html: does now feature grouping.

QfqForm.js: Form refresh is now known as form update. Form updates receive more elaborate response from server.

Added QfqNS.Element.getElement() function. Elements can now be set readonly/disabled. Renamed QfqNS.Element.Input to QfqNS.Element.Text.

Gruntfile.js: renamed js files qfq-jqw.* to qfq.*.
package.json: renamed qfq-jqw to qfq

Updated mocks to reflect changes.
Added less/qfq-plain.css.less.