More alertserver fixes

- Absolute path to token file
- Fix more flags

BUG=skia:3036

Review URL: https://codereview.chromium.org/690343002
Yet more alertserver fixes

BUG=skia:3036
TBR=jcgregorio

Review URL: https://codereview.chromium.org/695993002
Polymerize ClusterSummary into <cluster-summary-sk>.

 - The /annotate/ endpoint has been updated to accept and return JSON.
 - Both the alerts and clustering pages have been updated to use <cluster-summary-sk>

BUG=skia:
TBR=stephana

Review URL: https://codereview.chromium.org/691053005