Update README release branch links.

README.md

@@ -1,8 +1,8 @@
 # Mamba: Markov chain Monte Carlo (MCMC) for Bayesian analysis in julia
 
-**julia 0.4:** [![Docs](https://readthedocs.org/projects/mambajl/badge/?version=release-0.7)](http://mambajl.readthedocs.org/en/release-0.7/)
+**julia 0.4:** [![Docs](https://readthedocs.org/projects/mambajl/badge/?version=release-0.8)](http://mambajl.readthedocs.org/en/release-0.8/)
 [![Mamba](http://pkg.julialang.org/badges/Mamba_0.4.svg)](http://pkg.julialang.org/?pkg=Mamba&ver=0.4)
-[![Build Status](https://travis-ci.org/brian-j-smith/Mamba.jl.svg?branch=release-0.7)](https://travis-ci.org/brian-j-smith/Mamba.jl)  
+[![Build Status](https://travis-ci.org/brian-j-smith/Mamba.jl.svg?branch=release-0.8)](https://travis-ci.org/brian-j-smith/Mamba.jl)  
 **julia 0.3:** [![Docs](https://readthedocs.org/projects/mambajl/badge/?version=release-0.4)](http://mambajl.readthedocs.org/en/release-0.4/)
 [![Mamba](http://pkg.julialang.org/badges/Mamba_0.3.svg)](http://pkg.julialang.org/?pkg=Mamba&ver=0.3)
 [![Build Status](https://travis-ci.org/brian-j-smith/Mamba.jl.svg?branch=release-0.4)](https://travis-ci.org/brian-j-smith/Mamba.jl)