- Inspired by Ere Maijala's work on #1268.

- Work done by Agnès Manneheut

- Replaces previous feedback system in a backward-compatible way.

- Fixes Java 9/10 compatibility issues.

- Without the explicit sync folder ownership option, Vagrant 2.2.0 fails to create the "vendor/" directory when when running `vagrant up` the first time.

- Relying on APPLICATION_ENV is simpler.

Otherwise Zend\Session\Config\SessionConfig::setStorageOption() throws an exception when it tries to call ini_set with session-specific settings. This would have happened at least when creating a \Zend\Session\Container.

Add timestamps to static image urls like is already done for js and css files so that images can be cached without risk of missing any updates.

- This allows embedding to work more consistently, even though the user experience is not the best.

- The LoggerAwareTrait already defines it.

If a user accidentally mistypes their login credentials, they are not returned to the page they were on after successfully logging in via ILS Authentication. There already exists a similar fix for when a non-logged-in user goes to MyResearch/Home (which initiates the login challenge page). This bug fix adds one for MyResearch/UserLogin, too, which is linked to in themes/bootstrap3/templates/header.phtml

    Note: Links to MyResearch/UserLogin can have parameters, e.g., UserLogin?method=ILS,
    which is why I perform a substring test here:

        if (0 === strpos($refererNorm, $mulNorm)) {

     instead of testing for equality:

        if ($refererNorm === $mulNorm) {

- Use cursorMark for fetching IDs in sitemap generator search mode (faster for large indexes).
- Simplify code to better separate retrieval mode-specific logic.
- Change default retrieval mode to "search" since "terms" may not behave as expected in some situations (e.g. when hidden filters are applied).