Replace HTTPie with curl in README, link to API doc

* `curl` is widely installed, and so writing the API examples with
  `curl` removes the HTTPie dependency.
* Let's link to the new REST.md to show off the API documentation.
* Mark the V1 API as deprecated to start moving users to the V2 API.
Reduce header visibility, too much bold
Reduce more bold text, focus on API examples
Merge pull request #130 from mesosphere/readme-v2-example

Replace HTTPie with curl in README, link to API doc
Fixed a typo in the REST docs for the `/v2/apps?cmd={command}` endpoint, regenerated `REST.md`.
Merge branch 'master' of github.com:mesosphere/marathon
Merge from airbnb:staging, modulo mesos version (0.15.0)
Add a table of contents to v2 API docs
Refer to "all running apps" for /v2/apps?cmd={command}

It doesn't list just one.
Merge pull request #133 from mesosphere/api-v2-toc

Add a table of contents to v2 API docs
- Made the initial delay before attempting task reconciliation a configurable value
- µ-clean-up in MarathonSchedulerService
Modified the logged text output when scheduled task reconciliation occurs
Make this a little more modular.
Upgraded Chaos dependency to latest release (0.5.2).  Added an override for the resource cache control header value to burst browser caches for static assets.
Merge pull request #135 from mesosphere/wip-cache-burst

Burst Browser Cache for Static Assets
Append "v=1" to bust cache for next JS request

Since this will go out with the release of Marathon that serves
"must-validate" cache headers, this version string only needs to be
updated once.

This pairs with commit 9cbf3a916930fc30392fedb8e6ab8851eab58c83, which
responds with "Cache-Control: max-age=0, must-revalidate".
Updated App model validation logic

Marathon UI doesn't allow scale and suspend operations, if cmd string is empty.
Cmd string can be empty if an executor and container.image are provided. Today,
executor and container.image cannot be provided through UI, but v2 API supports it.

This commit introduces an additional check, that verifies if executor and
container.image are provided, if cmd string is empty.
Updated image check logic, to only check for docker instead of docker:///
Line length.
Allow requests with no ports. Addresses #138.