DFG integration roadmap IIF v0.6 0.8

Current version IIF 0.5.5 (April 2019)

• IIF v0.6.x will be tree based initialization, marginalization, etc.
• IIF v0.7.x is first integration of DFG, hack this hack that.
  • This will be an in-memory version, but will have a well defined interface that we can use to replace IIF code
• IIF v0.8.x fix all the issues and API in welding old IIF with DFG to get the desired behavior.
  • We should have the cloud versions of the interface and Terminus (mirror local/cloud) should be available