Replication

Add views and templates for replication task list and new task creation
Enable / disable for replication tasks
Write a wrapper for checking status of services, moving low level logic down
the layers.
Refactor Smart probe dispatcher and worker code to be more resilient, log
errors more appropriately. Remove deprecated stap.py
Fixes #146

Refactor proc retreiver to be more resilient.
Fixes #146

Refactor service monitor to be more resilient.
Fixes #146

Update smart manager service as required by changes to child services
Display replica trail for replicas
Merge branch 'issue#249_replication' of git://github.com/sujeetsr/rockstor-core into sujeetsr-issue#249_replication
Update run_command so that exception raising can be turned off.
Bugfix: Services stay in on state even when they fail to start.
Update replication model to save all state transitions properly.
Add pagination support for replica trail
Update replication scheduler and sender for the updated data model
simplify service api to support only config, start and stop.
Update nis and nfs apis to be transparent with rpcbind, the shared service.
Replication

Add start, end, duration, status columns for replica trails
Pagination for replica trails
Merge pull request #250 from schakrava/issue#146

Issue#146
Update replication model to store user_tag information