Fix instance summary visualisation.

Bugs closed: AURORA-755

Reviewed at https://reviews.apache.org/r/26095/
Upgrade to gradle 2.1

Reviewed at https://reviews.apache.org/r/26113/
Dropping assert on empty desired instances set.

Bugs closed: AURORA-756

Reviewed at https://reviews.apache.org/r/26102/
Fail the build on lack of test coverage.

Reviewed at https://reviews.apache.org/r/26123/
replace 143 kB favicon with 2 kB version.
Merge branch 'master' into jcohen/static-assets
Update LICENSE w/ new locations, add dygraphs, dygraphs extras.