Update to Bootstrap 3 RC1

Just updated to the Boostrap 3 feature branch of the Rails gem.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Add tabs to differ between analysis and statistics

For each metric I would like to make two views available. The first is
analysis. Analysis should be used to understand the metric results by
viewing their effect on the metadata records. The second is statistics,
giving an interview over the score distribution.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Display distribution of response codes

Added the code to display the distribution of response codes. This
should be visualized with a pie chart or similar in upcoming commits.

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