Update README.md

[menicosia]

Mostly added info to help people to notice and install either VirtualBox or VMware Fusion, a couple of usage/expectation suggestions, and finally a change to the call to GitHub from ssh to http since I think that works more universally.

(For whatever reason, my call to clone via git@github failed, but worked when I used http.)

[cfdreddbot]

Hey menicosia!

Thanks for submitting this pull request!

All pull request authors must have a Contributor License Agreement (CLA) on-file with us. Please sign the appropriate CLA (individual or corporate).

When sending signed CLA please provide your github username in case of individual CLA or the list of github usernames that can make pull requests on behalf of your organization.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this. You can view the current status of your issue at: https://www.pivotaltracker.com/story/show/86677698.

[davidwadden]

Thanks for taking the time to submit this PR. Due to compatibility issues, we no longer support VMWare Fusion as a provider until we've had time to shake out that configuration.

I'm closing this for now, if you wish to re-submit this against a newer revision or contribute in the future, please sign our Contributor License Agreement listed in the above comment.