Updates to README. (#366)
Updates to README. (#366)

* Removed trailing 'DC/OS' from overview. The name 'DC/OS SDK' implies this is for DC/OS.

* Add text describing current alpha status to better set user expections.

comptelfwd/dcos-commons,adragomir/dcos-commons,adragomir/dcos-commons,tobilg/dcos-commons,mesosphere/dcos-commons,tobilg/dcos-commons,vishnu2kmohan/dcos-commons,comptelfwd/dcos-commons,vishnu2kmohan/dcos-commons,tobilg/dcos-commons,comptelfwd/dcos-commons,mesosphere/dcos-commons,comptelfwd/dcos-commons,adragomir/dcos-commons,vishnu2kmohan/dcos-commons,tobilg/dcos-commons,comptelfwd/dcos-commons,mesosphere/dcos-commons,tobilg/dcos-commons,mesosphere/dcos-commons,vishnu2kmohan/dcos-commons,mesosphere/dcos-commons,adragomir/dcos-commons,adragomir/dcos-commons,comptelfwd/dcos-commons,vishnu2kmohan/dcos-commons