Update some links.

Author: chriseth

CONTRIBUTING.md

@@ -12,14 +12,11 @@ If you know C++, you can help by submitting pull requests (see below).
 We try to keep a list of [good tasks to start with](https://github.com/ethereum/webthree-umbrella/labels/good%20first%20task).
 Please get in contact on gitter if you have any questions or suggestions.
 
-We keep backlogs of tasks in different sites, depending on the subproject:
+The backlog is kept in github issues with an overview in our
+[waffle board](https://waffle.io/ethereum/webthree-umbrella),
+with the exception of Solidity, which has its own [backlog](https://www.pivotaltracker.com/n/projects/1189488).
 
- * [Solidity Backlog](https://www.pivotaltracker.com/n/projects/1189488)
- * [Mix Backlog](https://github.com/ethereum/mix/issues)
- * [Eth Backlog](https://www.pivotaltracker.com/n/projects/1510366)
-
-Finally, there is a [waffle board](https://waffle.io/ethereum/webthree-umbrella) containing all issues from all subrepositories.
-This is especially useful to keep track of pull requests pending reviews
+The waffle board is also useful to keep track of pull requests pending reviews
 (if you switch the filter on the top right to "pull requests only").
 
 

README.md

@@ -41,7 +41,7 @@ External contributions are more than welcome! We try to keep a list of tasks tha
 newcomers under the tag [good first task](https://github.com/ethereum/webthree-umbrella/labels/good%20first%20task).
 If you have any questions, please ask in our [gitter channel](https://gitter.im/ethereum/cpp-ethereum).
 
-Please refer to the file [CONTRIBUTING.md] for some guidelines.
+Please refer to the file [CONTRIBUTING.md](CONTRIBUTING.md) for some guidelines.
 
 All new contributions are added under the MIT License. Please refer to the `LICENSE` file in the root directory.
 To state that you accept this fact for all of your contributions please add yourself to the list of external contributors like in the example below.