Updated README with jdk8, and maven customization
Updated README with jdk8, and maven customization

JIoJIaJIu/heroku-buildpack-java,kimonocloud/natsu-buildpack-java,Parlio/heroku-buildpack-java,noncreativetype/sms,wishtack/heroku-buildpack-java,Vincit/heroku-buildpack-java-nodejs,hpcloud/heroku-buildpack-java,bluebreezecf/heroku-buildpack-java,neilgandhi/heroku-buildpack-java,franciscocpg/heroku-buildpack-java,noncreativetype/sms,franciscocpg/heroku-buildpack-java,heroku/heroku-buildpack-java,heroku/heroku-buildpack-java,wishtack/heroku-buildpack-java,neilgandhi/heroku-buildpack-java,Scalingo/java-buildpack,noncreativetype/sms,bluebreezecf/heroku-buildpack-java,Scalingo/java-buildpack,JIoJIaJIu/heroku-buildpack-java,Parlio/heroku-buildpack-java,hpcloud/heroku-buildpack-java,Vincit/heroku-buildpack-java-nodejs,kimonocloud/natsu-buildpack-java