Fix styles on repository and metric selector

Just cleaned two rules up for proper functioning of the repository and
metric selector in the breadcrumb.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Rename helper module to generate the reports

I have renamed the module which was previously namespaced under
Report::Metrics to Analysis::Metrics.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Add Raphaël and gRaphaël

For visualizing statistics I have added the Raphaël JavaScript library.
IN particular the g.pie-min.js will be used to display pie charts.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Work towards link checker pie chart

I have added some initial code for the pie chart construction. The pie
chart is already drawn with some values from the demo example. Also I
have moved a lot of the old specific metric views to another directory.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Generate the pie chart from the actual results

Now the pie chart is generated from the actual link checker report
results. For this I had to add some more code to make the data available
via gon.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Complete pie chart to show link checker responses

This commit finishes the implementation of a pie chart visualizing the
distribution of link checker responses. There was a problem if the pie
chart would be rendered on an invisible element. This would lead to a
stacked legend. I have fixed it by creating the pie chart when the tab
is clicked.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>