Set better JVM defaults for various dyno sizes
Set better JVM defaults for various dyno sizes

jcf/heroku-buildpack-jvm-common,pwalczak/testagapw,Scalingo/jvm-common-buildpack,pwalczak/testagapw,heroku/heroku-buildpack-jvm-common,Scalingo/jvm-common-buildpack,jcf/heroku-buildpack-jvm-common,heroku/heroku-buildpack-jvm-common