Add the documentation for the expression and languages

Hi

The FUSE IDE has a link to expression and languages from this page (click documentation tab)
http://fusesource.com/products/fuse-ide-camel/

Its this documentation I am talking about
http://fusesource.com/docs/ide/camel/1.0/expression_lang/index.html

I think we should have that as well for the Fuse MR documentation page
http://fusesource.com/products/enterprise-camel/#documentation