Update step-1---deploying-your-web-application-to-the-gigaspaces-environment.markdown

1. Cannot deploy 3 instances with max-per-machine=2 -> Changed "2" to "3"
2. gs-agent does not start with 3 GSCs but with 2 -> Added a step for starting the third GSC
Merge pull request #283 from yohanakh/patch-4

Update step-1---deploying-your-web-application-to-the-gigaspaces-environ...