Add jruby-1.7.16.2

JRuby 1.7.16.2 has been released to address CVE-2014-8090.  All users
are encouraged to upgrade

http://jruby.org/2014/12/08/jruby-1-7-16-2.html
ruby-build 20141208
Add jruby-1.7.17

http://www.jruby.org/2014/12/09/jruby-1-7-17

Highlights:
  56 issues fixed for 1.7.17
  native crypt()
  Fixed bad encoding of string interpolated within backticks
  popen2+ now works properly with env hash
  improvements to align MRI and JRuby FFI
  updated stdlib to 1.9.3p392 (+ rexml security fixes)
  tzdata updated
Merge pull request #681 from dkoprov/jruby-1.7.17

Add jruby-1.7.17
ruby-build 20141210
rbx 2.3
added rbx 2.4.0 and 2.4.1
Merge branch 'master' of github.com:bl4ckn0de/ruby-build