Tigon README.md

Draft of README.md file. This is the file that appears as the "home page" for the GitHub repo.
@awholegunch There can be two options here. One to run tests and one option to skip tests. Either way we should recommend the users to set MAVEN_OPTS="-Xmx3056m  -XX:MaxPermSize=128m"
For building and running tests : mvn clean package
For only building : mvn clean package -DskipTests