JRuby 9000 (the next major release) includes a backend that supports a
new JVM JIT compiler called Graal. Graal is based on OpenJDK but hasn't
been released yet.

http://openjdk.java.net/projects/graal/

Fix Java 7 detection

Java on most (all?) platforms directs `-version` output to STDERR.

Add mruby 1.0.0.

Update MagLev branch from master-1.9 to master

Leaves rubies >= 2.0 vulnerable to CVE-2013-6393

Ensures that color is off if the stderr stream is not a terminal

Require Java 7 for jruby-9000-dev.

Add support for rbx-2.2.5

Add JRuby 9000 snapshot.

This should plug the vulnerability to CVE-2013-6393 (and fix #504)
that can still occur in certain systems: If the ruby build process
couldn't find a libyaml that worked, it would build its own vendored
libyaml, which was 0.1.4 (and is vulnerable).

Instead, specify that the build always should install the latest
libyaml & build against that.

Actually resolves https://github.com/sstephenson/ruby-build/issues/499.

Closes https://github.com/sstephenson/ruby-build/issues/499.

Add MAKE_INSTALL_OPTS for packages

Closes #483

install(1) defaults to file mode 0755 which is inappropriate for Ruby
definitions

Also fix the ordering of make install arguments