Update README.md and move Doxygen/images in docs

README.md

@@ -1,5 +1,5 @@
 OpenPMD plugin for VisIt
-========================
+================================================================================
 
 #### Table of Contents
 1. [Presentation](#Presentation)
@@ -8,42 +8,53 @@ OpenPMD plugin for VisIt
 4. [To be implented/improved](#To-be-implemented/improved)
 
 ## Presentation
--------------------
+--------------------------------------------------------------------------------
 
-This repository contains the sources for development of an OpenPMD plugin for the visualization software [VisIt](https://wci.llnl.gov/simulation/computer-codes/visit).
+This repository contains the sources of an OpenPMD plugin for the visualization
+ software [VisIt](https://wci.llnl.gov/simulation/computer-codes/visit).
+This plugin now handles OpenPMD files in HDF5.
+It works both in sequential and parallel.
+The plugin can read Cartesian and axisymmetrical geometry (referred to
+as `thetaMode` in the standard).
 
 ## Repository and code structure
-------------------------------------
+--------------------------------------------------------------------------------
 
 #### Files
 
 This repository contains:
 
-- the C++ source files
-- an xml file `OpenPMD.xml` essential for building the plugin
-- a Doxygen documentation (in the directory `/Doxygen`) that describes the different classes
-- this `README.md` file
+- The C++ source files
+- An xml file `OpenPMD.xml` essential for building the plugin with VisIt tools
+- The directory `docs` that contains the documentation
+- The resources to generate a doxygen doc (in the directory `/Doxygen`) that describes the different classes
+- This `README.md` file
 
-Sources are composed of files generated by Visit:
+Sources are composed of files generated by VisIt:
 
 - `avtOpenPMDFileFormat.C`: class for reading and converting file format in vtk
 - `OpenPMDEnginePluginInfo.C`
 - `OpenPMDMDServerPluginInfo.C`
 - `OpenPMDCommonPluginInfo.C`
 - `OpenPMDPluginInfo.C`
 
-And external C++ classes developped for reading OpenPMD files:
+And external C++ classes developed for reading OpenPMD files:
 
 - `PMDFile.C`: Open, scan and print OpenPMD file structures
 - `PMDiteration.C`: class for the iteration groups
 - `PMDField.C`: class for the field groups
 - `PMDParticle.C`: class for the particle groups
 
+The `docs` directory contains:
+
+- [CONTRIBUTING.md](./docs/CONTRIBUTING.md) with instructions on how to contribute to this plugin
+- [ISSUE_TEMPLATE.md](./docs/ISSUE_TEMPLATE.md)
+
 #### How works this plugin
 
-Visit plugins basically read outputs with some specific code or data formats to convert them internally into vtk readable data.
+VisIt plugins basically read outputs with some specific code or data formats to convert them internally into vtk readable data.
 
-![alt text](./Doxygen/images/class_description.png "Classes")
+![alt text](./docs/images/class_description.png "Classes")
 
 #### How to generate the Doxygen documentation