Update tech landscape: AWS GG, OCF, OpenFog

[mmccool]

Update tech landscape to address some issues and document some additional technologies.
Updates: OCF is not mentioned and needs to be documented better.
New: AWS Greengrass and OpenFog need to be added, as emerging edge computing mechanisms/standards.

[mmccool]

Note: Work in Progress. So far I've only made some minor tweaks, as follows:

• oneM2M data model section was just a cut-and-paste of the SAREF entry, so I reverted it and marked it as TODO. If it's just the SAREF model IMO that should be noted under the SAREF entry.
• Added note under RAML and OAI that RAML is used for OIC and OCF data modeling and OAI is used for OCF introspection.
  NOTE: OCF is not mentioned anywhere in the document, and should be. Only OIC is cited, and the merger of AllJoyn and OIC is not mentioned. I will likely add "OCF" as a new entry and leave OIC and AllJoyn as they are (they will still exist, but OCF will be forward-compatible with them).

[mmccool]

Ready for merge now as far as I am concerned. Please comment; I will merge in a week or so if no issues noted.

[mjkoster]

There is another data model used by oneM2M for instances of things called SDT (Smarthome Device Template) which came from the work that was done in the Home Gateway Initiative (HGI).

[mmccool]

Added SDT reference, took out blank oneM2M data model section, but added reference to some of oneM2M's abstract information model work in the SDT section. Should there be a separate section for oneM2M information/data models?

[mmccool]

If Dave R reviews this and says yes I will merge.

[sebastiankb]

Is this PR still relevant?