Implement rake task to aggregate open licenses

The rake task has now been implemented. It harvests the open licenses
from the repositories. A license is overwritten, if a repository uses
the license as an open license.

Although an advisory board might disagree, I will use this policy for
Metadata Census, at least for the time being.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Colorize resource size table on the accuracy page

Just added some colors, adjusted the table width and added a different
output to the resource size table of the accuracy metric page.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Write Rake task to list snapshots with relative id

I have written another Rake task. It just lists the available snapshots.
I want to use this to ease the Rake task for scheduling metric worker.
Instead of entering a snapshot date, I will use this relative
identifier.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Write Rake task to schedule metric tasks

I have implemented another Rake test which can scheduler all or certain
metric computations. It is now very easy to schedule all possible tasks.

$ rake schedule[govdata.de, 2013-11-09, complenetess]

$ rake schedule[govdata.de, 2013-11-09]

$ rake schedule[govdata.de]

$ rake schedule

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