Merge commit 'origin/branch-2.1' into feature/containers

* commit 'origin/branch-2.1': (66 commits)
  Add automated disk repair changes to design doc
  Add review script
  Implement “gnt-node physical-volumes” command
  Add new opcode to list physical volumes
  storage: Use constants.py instead of local constants
  storage: Fix semantics for directory size
  Add “gnt-job watch” command
  jqueue: Fix error when WaitForJobChange gets invalid ID
  jqueue: Update message for cancelling running job
  cmdlib: Change tasklet logging to debug level
  rapi: Add /2/nodes/[node_name]/migrate resource
  gnt-node: Use new opcode to migrate node
  cmdlib: Add new opcode to migrate node
  rapi: Add default parameter to _checkIntVariable
  cmdlib: Add logging for tasklets
  cmdlib: Fix tasklets handling if no tasklets are added
  rapi: Add /2/[node_name]/evacuate resource
  Add information about storage units framework
  Add RPC calls for storage unit list
  Add first implementation of generic storage unit framework
  ...