fixed usage syntax for --json flag
removed outdated/incomplete docs and added link to dev portal
[DOC] Add installation guide for Mac
[FEATURE] Reorganize ProcessManager, create ProcessSet.

[TASK] Rename GatewayProcessManager to ProcessManager.

[TASK] Rename GatewaydProcessSet to ProcessSet.
[TASK] Clean up ProcessManager behavior.
[DOC] Correct documentation, config.json not config.js.

[FOLD] Use config.json not config.js in mac install doc.
[TASK] Add release notes, bump minor version.