Work towards #56: Splitting up the README

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

flyweight/index.md

@@ -0,0 +1,25 @@
+---
+layout: pattern
+title: Flyweight
+folder: flyweight
+categories: pattern_cat
+tags: pattern_tag
+---
+
+**Intent:** Use sharing to support large numbers of fine-grained objects
+efficiently.
+
+![alt text](./etc/flyweight_1.png "Flyweight")
+
+**Applicability:** The Flyweight pattern's effectiveness depends heavily on how
+and where it's used. Apply the Flyweight pattern when all of the following are
+true
+* an application uses a large number of objects
+* storage costs are high because of the sheer quantity of objects
+* most object state can be made extrinsic
+* many groups of objects may be replaced by relatively few shared objects once extrinsic state is removed
+* the application doesn't depend on object identity. Since flyweight objects may be shared, identity tests will return true for conceptually distinct objects.
+
+**Real world examples:**
+
+* [java.lang.Integer#valueOf(int)](http://docs.oracle.com/javase/8/docs/api/java/lang/Integer.html#valueOf%28int%29)