Use personal master version of Graal repo

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Completed repo url

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Added build script for Graal

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Added scripts for graal, java 7 and 8 to simplify benchmarking

Signed-off-by: Stefan Marr <git@stefan-marr.de>