minimal Java source version for jdk-10.0.1;
renamed jvmpath to platform_path;
more formal isabelle makedist from repository; --HG-- rename : Admin/Release/makedist => Admin/lib/Tools/makedist
more robust command invocation via ISABELLE_JDK_HOME or SCALA_HOME (NB: bash exec requires genuine executable, not function);
ISABELLE_JDK_HOME settings variable points to JDK with javac and jar (not just JRE); update for prospective jdk1.7.x component;
simplified build/bootstrap of graph browser -- avoid make;