Work towards #56: Splitting up the README

I did the job and splitted up the readme, hopefully everything was
splitted correctly...

execute-around/index.md

@@ -0,0 +1,18 @@
+---
+layout: pattern
+title: Execute Around
+folder: execute-around
+categories: pattern_cat
+tags: pattern_tag
+---
+
+**Intent:** Execute Around idiom frees the user from certain actions that
+should always be executed before and after the business method. A good example
+of this is resource allocation and deallocation leaving the user to specify
+only what to do with the resource.
+
+![alt text](./etc/execute-around.png "Execute Around")
+
+**Applicability:** Use the Execute Around idiom when
+
+* you use an API that requires methods to be called in pairs such as open/close or allocate/deallocate.