Update VERSION and README.md for 0.3 release. (#995)

Author: halfflat

README.md

@@ -10,11 +10,13 @@ An installation guide and library documentation are available online at [Read th
 
 ### Citing Arbor
 
-It is possible to cite specific versions of Arbor used to run a simulation via Zenodo:
+The Arbor software can be cited via Zenodo: [![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.1459678.svg)](https://doi.org/10.5281/zenodo.1459678).
+
+Previous versions of Arbor can be cited specifically:
 * Version 0.2: [![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.2583709.svg)](https://doi.org/10.5281/zenodo.2583709)
 * Version 0.1: [![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.1459679.svg)](https://doi.org/10.5281/zenodo.1459679)
 
-The following BibTeX can be used to cite Arbor:
+The following BibTeX entry can be used to cite Arbor:
 
 ```
 @INPROCEEDINGS{

VERSION

@@ -1 +1 @@
-0.2.3-dev
+0.3