Adds ContainerHeadroomEnricherTest, and fixes

- Don’t repeatedly publish “ok”
- Fix setting highThreshold (previously would never auto-scale because
  highThreshold set as `max(utilisation, calculatedVal)`)
Updated tomcat and solr blueprint
Merge pull request #73 from aledsage/fix/ContainerHeadroomEnricher

Adds ContainerHeadroomEnricherTest, and fixes
Merge pull request #72 from aledsage/fix/various-20141127

Fix/various 20141127
Merge pull request #75 from duncangrant/fix/tomcat-solr-blueprint

Updated tomcat and solr blueprint