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.
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
Keep "Drag photos here" area

Add a setting "keep_droptext" to jquery.plupload.queue. If enabled,
the last element in the plupload filelist that serves as a big drop
area for adding files, will be kept even after files have been added.

Fixes #365

Note: Minified versions of the Javascript files and asset cache have NOT
bee updated.
Lossless optimisation of Beisel2 graphics

Google Pagespeed suggested optimising some image files that are part
of the Beisel 2.0 theme.

Running them through the lossless Yahoo online optimisation service at
http://www.smushit.com/
Reduces the total size of beisel2.0/images from 707.2 to 658.9 KB.
Major improvement: pattern.png goes from 48.8 to 8.5 KB.

Improves #649
Merge branch 'setup-improvements' of https://github.com/oscherler/openphoto-frontend into pr-868
Code formatting to remove some curly braces. #730
Merge branch 'label-styling' of https://github.com/pixelistik/frontend into pr-897
Merge branch 'upload-prevent-wrong-drop' of https://github.com/pixelistik/frontend into pr-898
Minifying JS and updating cache key. #365 #898
Merge branch 'optimise-beisel2-images' of https://github.com/pixelistik/frontend into pr-899
Fixing typo. Closes #907
Add unit tests for PiwikPlugin

Set up folder and configuration for PHPUnit tests for plugins.

Create tests for the PiwikPlugin, testing for correct integration
of the Javascript code into header and footer of pages.
Hide close button if Batch edit info box

The info box should not be closeable, as it contains the reset button
for the batch edit pins.

This is not easy to target in CSS, adding an extra wrapper div for
this specific alert box.

Fixes #865