Merge pull request #179 from telefonicaid/hardening/175

hardening/175
Fix the behaviour when trying to create elements in a deleted but not purged state
Fix issues raised during code review
Merge pull request #182 from telefonicaid/bug/101

bug/101
Merge pull request #183 from telefonicaid/bug/101

bug/101 (into develop)
Fix the exceptions trown by MySQL sink
Delete unnecesary white spaces
Merge pull request #186 from telefonicaid/bug/184

bug/184 (into develop)
Document the management interface and the management port configuration
Get the last git commit when compiling the code
Implement a simple management interface
Add an utility function for getting the last git commit
Fix issues raised during code review
Merge pull request #192 from telefonicaid/backlog/169

backlog/169
Document how to configure a round robin-based load balancing among two sinks
Add to the configuration template a round robin-based load balancing among two sinks
Identify the author of the the log traces
Add a CygnusLog class which extends Logger from log4j
Split into two different tamplates the basic usage and the load balancing usage
Delete the jetty server attribute from OrionRestHandler