Add readme for p2 build of emfjson.

Author: ghillairet

emfjson-p2-build/README.md

@@ -0,0 +1,23 @@
+EMFJson P2 Build
+---
+
+To build emfjson p2 repository from source, follow the following instructions.
+
+```
+git clone https://github.com/ghillairet/emfjson.git
+```
+
+```
+cd emfjson/emfjson-p2-build
+```
+
+```
+mvn clean verify
+```
+
+This builds a p2 repository in emfjson-repository/target/repository folder.
+Add this folder to your eclipse plugin manager to install the bundles in your eclipse installation.
+
+> If you are not using the eclipse Mars release (version 4.5), before trying to install the emfjson bundles, 
+add the orbit p2 repository that contains the jackson bundles version 2.5 or superior 
+(http://download.eclipse.org/tools/orbit/downloads/drops/R20150519210750/repository/).