add libffi dep for berks >= 3.0
removing studio compiler, aux gem bindir fix

- aux gems should have gone into /opt/chef/embedded/bin
add support for 20130712-3.1 version
interpolate version string
add support for using 2.4.2 version
add support for 2.9.1 version

removing libicu prevents builds on macs from finding the libicu
libraries
add support for 1.1.28 version

- solaris obviously needs a libtool version bump
remove solaris studio compiler cruft
nokogiri 1.6.1 support

- we need to override nokogiri's bundled libxml2 and libxslt which
  will link themselves against system libs and their deps will fail
  our healthcheck
- also on macs we need to point pkg-config at the embedded pkg-config
  files otherwise we'll wind up linking against system libs (this should
  be baked into omnibus by default!)
remove solaris studio compiler cruft
remove solaris studio compiler cruft
remove solaris studio compiler cruft
support building ruby-2.1.0
support building rubygems 2.2.1
remove solaris studio compiler cruft
support buildling 1.2.8
add chefdk-specific gems
add libffi definition for berks3
use verison instead of gem_version
fix rubocop for mac