Add doc about enabling SSL and basic auth

This addresses part of issue #432.
added ConcurrentSet and use it in TaskTracker
Merge pull request #469 from mesosphere/wip-tasktracker-drexin

added ConcurrentSet and use it in TaskTracker
Added queue, deployment, and task embedding docs

- Deleted REST template
Added docs for Chaos endpoints
Link to local Marathon site in README

Make it apparent the Marathon site is served at “/marathon”.
Clarify SSL configuration steps

* Use “.pem” extension for certificate since it is the common format
  received from certificate authorities.
* Use “name” and “srcalias” to support multiple certs in PKCS format.
* Append “.jks” extension for “Java Keystore”.
Merge pull request #487 from mesosphere/REST-doc-updates

Rest doc updates
Add missing 'n' to 'unencrypted'
Link to HTTPS version of Marathon as final step
Refer to Java keystore as standard “.jks”
Use env variables for passwords

This makes automation easier and assigns meaningful names to passwords.
Use env variable for all passwords
Add Sailthru to the "Companies Using Marathon" list!
Merge pull request #490 from adgaudio/master

Add Sailthru to the "Companies Using Marathon" list!
Merge pull request #484 from mesosphere/ssl-basic-auth-doc

Add doc about enabling SSL and basic auth
Update docker to build from source