Fix error in the scheduler module and style up

Just a small error and style the repository show page further.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Add flot graph to visualize the quality change

In order to give the repository show page enough content I have added
the Flot library to generate a line chart. The line chart shows how the
quality has changed over time. I will use Flot to visualize the timeline
for all repositories, too.

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

A timeline in the form of another Flot line char graph has been added.
It only displays snapshot scores if there are more than just one.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Add modal to host metric weight sliders

Currently, the only settings on the settings options will be the
weighting sliders. This is necessary to make this option available
everywhere else, too.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Implement weight slider functionality

Now changing the weight slider also submits the updated numbers to the
server.

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