Use Omnibus copy/delete on Windows instead of cp/rm

Using cp would presume we're running under MinGW, which is not currently
installed on the build slaves by https://github.com/opscode-cookbooks/omnibus
add libffi dep to chef

chef with ffi-yajl now needs this dep
Merge pull request #266 from opscode/lcg/libffi-dep-to-chef-gme

add libffi dep to chef
Adding a software definition for libossp-uuid

See http://www.ossp.org/pkg/lib/uuid/

This is notably useful to be able to build pgSQL with the uuid-ossp module
(http://www.postgresql.org/docs/9.1/static/uuid-ossp.html)
Merge pull request #264 from opscode/btm/libyaml-windows-cp

Use FileUtils.cp on Windows instead of cp
Create libyaml-windows directory at build time, not compile
Create openssl-windows directory at build time, not compile
Do not execute commands at compile time
Use windows_safe_path when shelling out on Windows
Clarify supported branches
General README and gemspec cleanup
Version omnibus-software with omnibus
Make Copyright header consistent
Cleanup appbundler
Cleanup autoconf
Cleanup automake
Cleanup berkshelf
Cleanup berkshelf2
Cleanup bundler
Cleanup bzip2