Merge tag '0.6.0' into develop

Release 0.6.0
Bumped version to 0.6
Merge pull request #8 from wealdtech/feature/version

Version.
Updates for latest version
Moved prefetch filter to wealdtech
Changed principal provider get() to getFromKey() to avoid potential clashes
Added sonar
Tidy-ups
Tidied up configuration
Merge tag '0.6.1' into develop

Fix for issue #9
Merge of issue #9
Merge pull request #11 from wealdtech/feature/0.7

0.7
Fix for change to Wealdtech core
Merge pull request #12 from wealdtech/feature/tidy

Tidy-ups for 0.7
Tidy-up
Merge pull request #13 from wealdtech/feature/0.7

0.7
Matching 0.9 spec
Updated tests and version number
Merge pull request #14 from wealdtech/feature/0.9

0.9
Use release version of Guava