Add release notes for 5.6.0

Author: lefticus

_posts/2015-01-17-release-5.6.0.markdown

@@ -0,0 +1,31 @@
+---
+title: Release 5.6.0
+tags: release
+---
+## [Release 5.6.0](https://github.com/ChaiScript/ChaiScript/releases/tag/v5.6.0 "Release 5.6.0")
+
+### Changes since 5.5.1
+* Throw exception on integer divide by 0
+* Add optional type specification to function declarations
+   
+  ```
+  def func(int i, j, double k) {
+    // i must be an int.
+    // j can be anything
+    // k must be a double
+    // normal conversion rules still apply
+  }
+   ```
+* Many minor fixes for compiler warnings
+* Add support for `std::future` and `std::async`
+  ```
+  var f := async(someFunction);
+  var f2 := async(someFunction2);
+
+  // someFunction and someFunction2 are running in parallel now
+  f.get();
+  f2.get();
+  ```
+* Fully support r-value returns, supporting move-only objects and reducing object copies
+
+