Merge pull request #236 from hsbt/switch-svn-to-git

Switch 2.0.0-dev and 1.9.3-dev to git since the svn->git mirror is back up.

share/ruby-build/1.9.3-dev

 install_package "yaml-0.1.4" "http://pyyaml.org/download/libyaml/yaml-0.1.4.tar.gz"
-install_svn "ruby-1.9.3-dev" "http://svn.ruby-lang.org/repos/ruby/branches/ruby_1_9_3" "HEAD" autoconf standard
+install_git "ruby-1.9.3-dev" "https://github.com/ruby/ruby.git" "ruby_1_9_3" autoconf standard

share/ruby-build/2.0.0-dev

 install_package "yaml-0.1.4" "http://pyyaml.org/download/libyaml/yaml-0.1.4.tar.gz"
-install_svn "ruby-2.0.0-dev" "http://svn.ruby-lang.org/repos/ruby/trunk" "HEAD" autoconf standard
+install_git "ruby-2.0.0-dev" "https://github.com/ruby/ruby.git" "trunk" autoconf standard