Add Clang.jl to CONTRIBUTING.

Remove links to wiki on Code Patterns and Type Hierarchy. These
could perhaps be updated and reinstated in the documentation.

CONTRIBUTING.md

@@ -14,10 +14,6 @@ Hi! Thanks for checking out Julia. If you have questions or problems, the [Julia
 
 ## Submitting your contributions
 
-### Contributing a Julia package
-
-Julia has a built-in [package manager](https://github.com/JuliaLang/METADATA.jl) based on git. A number of [packages](http:https://docs.julialang.org/en/latest/packages/packagelist/) across many domains are already available for julia. Developers are encouraged to provide their libraries as a Julia package. The Julia manual provides instructions on [creating julia packages](http:https://docs.julialang.org/en/latest/manual/packages/).
-
 ### Contributing to core functionality or base libraries
 
 The Julia team uses [GitHub issues](https://github.com/JuliaLang/julia/issues) to track and discuss problems, feature requests, and pull requests.
@@ -28,6 +24,12 @@ Before submitting, make sure that all tests pass by running `make testall`. Add
 
 *By contributing code to Julia, you are agreeing to release it under the [MIT License](https://github.com/JuliaLang/julia/tree/master/LICENSE.md).*
 
+### Contributing a Julia package
+
+Julia has a built-in [package manager](https://github.com/JuliaLang/METADATA.jl) based on git. A number of [packages](http:https://docs.julialang.org/en/latest/packages/packagelist/) across many domains are already available for julia. Developers are encouraged to provide their libraries as a Julia package. The Julia manual provides instructions on [creating julia packages](http:https://docs.julialang.org/en/latest/manual/packages/). 
+
+For developers who need to wrap C libraries so that they can be called from Julia, the [Clang.jl](https://github.com/ihnorton/Clang.jl) package can help generate the wrappers automatically from the C header files.
+
 ## Getting help
 
 While getting familiar with Julia, remember to check out [the docs](http:https://docs.Julialang.org/en/latest/), keeping in mind that they are [searchable](http:https://docs.Julialang.org/en/latest/search/). (If you use a script blocker then you'll have to unblock that page.) The [source code](https://github.com/JuliaLang/julia) is an excellent source of examples (and it's mostly pretty approachable). If you're still stumped, post something on [the dev list](https://groups.google.com/forum/?fromgroups#!forum/julia-dev), but you may want to search the archives first to see if there's already been a discussion about what you're stuck on.
@@ -41,11 +43,10 @@ While getting familiar with Julia, remember to check out [the docs](http:https://docs.
  - **Source code:** <https://github.com/JuliaLang/julia>
  - **Git clone URL:** <git:https://github.com/JuliaLang/julia.git>
  - **Documentation:** <http:https://julialang.org/manual/>
+
 * Design of Julia
  - [Julia: A Fast Dynamic Language for Technical Computing](http:https://julialang.org/images/julia-dynamic-2012-tr.pdf)
-* Working with Types
- - [Some Type Patterns](https://github.com/JuliaLang/julia/wiki/Code-Patterns)
- - [The Type Hierarchy](https://github.com/JuliaLang/julia/wiki/Types-Hierarchy)
+
 * Using GitHub
  - [Using Julia with GitHub (video)](http:https://www.youtube.com/watch?v=wnFYV3ZKtOg&feature=youtu.be)
  - [Using Julia on GitHub (notes for video)](https://gist.github.com/2712118#file_Julia_git_pull_request.md)