PiwikPlugin should also track modal photo views

Until now, the Piwik tracker code inserted by the PiwikPlugin would
only do tracking at page load, thus missing any modal AJAX photo views.

This adds a piece of Javascript to the PiwikPlugin, which installs
a listener on the custom event that gets fired when a modal photo
link is clicked.

The updated page title and URL are then reported to the Piwik tracker
as an additional page view.
Merge branch 'piwik-plugin' of https://github.com/pixelistik/frontend into pr-856
Firing a `photo:viewed` when a photo is loaded (ajax or full page). #856

Updating the Piwik plugin to track photo detail views using the custom event.
All other viewed are tracked normally from the `renderHeader` method.
Removing the ‘required’ attribute for the MySQL password input in setup.

To match the server-side removal of ‘required’.
Fixed setup writeConfigFile() to only log safe and useful values. #730

It used to log the whole contents of the session, including passwords and secret keys.
Fixing typos in fileSystem session key.

Although they have no noticeable effect… yet.
Improved writeConfigFile() logging.

writeConfigFile() logs key and value for known safe values, and key only otherwise.
Cleanup before starting: fix credentailDelete typo.
Add a modal dialogue to display OAuth credentials in Manage Applications.
Style manage applications additions.
Minify JavaScript.
Fix applications page CSS after rebase.
Merge branch 'show-oauth' of https://github.com/oscherler/openphoto-frontend into pr-894
Removing unused manage navigation template. #638
Updating cache key for CSS. #841
Remove redundant modal dialogue closing code.
Merge branch 'show-oauth' of https://github.com/oscherler/openphoto-frontend into pr-896
Updating JS cache key and removing click handler from template.php. #896
Change Piwik calls to async model

There was a possible race condition because photo:viewed can be fired
before the Piwik script is loaded and created the Piwik object.
Fix hover style on Beisel 2.0 tag list

Remove unneeded <span> wrapped around the tag links, apply classes to links
directly, just like on the photo detail page.

The hover state now doesn't lead to orange text on orange background anymore. Also,
the link area now matches the entire label box, not just the writing inside.

Fixes #845