CLOUDIFY-1587 Ongoing refactoring of agent health probe

Added Challenge logic, and TaskBasedAgentHealthProbe managed its own life cycle for unreachability detection
CLOUDIFY-1587 Ongoing refactoring of agent health probe

Changed version of guava to 14.0 in kvstore
Merge remote-tracking branch 'origin/feature/1587_refactor_agent_liveness' into feature/1587_refactor_agent_liveness

Conflicts:
	orchestrator/src/main/java/org/cloudifysource/cosmo/service/ServiceGridOrchestrator.java
CLOUDIFY-1587 Ongoing refactoring of agent health probe

Fix codestyle issues