Add a GitblitPlugin class for plugins to extend
Expose the plugin manager to the webapp
Improve ticket branch ref deletion push handling
Start plugin manager last to allow plugins deterministic access to the other managers
fix NullPointerException in ITicketService and add TestCase
Update to pf4j 0.8.0
Enforce plugin-requires attribute
Documentation
Update to SLF4J 1.7.5
Removed obsolete Gravatar profile code
Merge pr-170 'ticket-fix' from https://github.com/lucidd/gitblit