Bugfixes

Hi Piwik team!

I push a lot of bugfixes introduced in the latest commits.

Corrections done:

* Segment Editor > click on "edit" a segment: the selector is hidden
* Menu > Enable the ExampleUI plugin. Then the Menu does not fit on one line. To solve this, the Site Selector should be less wide/smaller font. 
* Site Selector > it pushes content down. Instead the site selector should appear on top of the content.
* On Manage > Websites, I cannot scroll to the right. There is no scroll bar.
* General > The down arrow is missing in Segment Editor grey box / Widgets & Dashboard boxes
* All Websites > sort icons are not visible in the table header
* Sparklines > Sparklines not working on Zeitgeist
* Sparklines > Sparklines point not working on PleinLune
* Sparklines > Sparklines not working on MultiSites plugin
* On Goals > Overview or Referers > Overview, click on a sparkline. It does not reload the graph and shows the message: The parameter 'columns' isn't set in the Request, and a default value wasn't provided.
* jQplot > Code in jqplot.js causes JS error: TypeError: this.params.yaxis is undefined,[Break On This Error] ,,formatString: '%d' if (typeof this.params.axes.yaxis.tickOptions == 'undefined') { this.params.yaxis.tickOptions = { formatString: '%d' }; } 

There is, according to me, one big bug remaining:

* jQplot > We lost the tooltips for all graphs. There are displayed only if your cursor go directly from the outside of the graph to the point.

Cheers,
Thomas.