explicitly test against Julia v0.6 and add PackageEvaluator v0.6 badge (#212)

Author: jrevels

.travis.yml

@@ -1,6 +1,7 @@
 language: julia
 julia:
     - 0.5
+    - 0.6
     - nightly
 notifications:
     email: false

README.md

@@ -1,7 +1,9 @@
 [![Build Status](https://travis-ci.org/JuliaDiff/ForwardDiff.jl.svg?branch=master)](https://travis-ci.org/JuliaDiff/ForwardDiff.jl) [![Coverage Status](https://coveralls.io/repos/JuliaDiff/ForwardDiff.jl/badge.svg?branch=master&service=github)](https://coveralls.io/github/JuliaDiff/ForwardDiff.jl?branch=master)
+
 [![ForwardDiff](http://pkg.julialang.org/badges/ForwardDiff_0.3.svg)](http://pkg.julialang.org/?pkg=ForwardDiff&ver=0.3)
 [![ForwardDiff](http://pkg.julialang.org/badges/ForwardDiff_0.4.svg)](http://pkg.julialang.org/?pkg=ForwardDiff&ver=0.4)
 [![ForwardDiff](http://pkg.julialang.org/badges/ForwardDiff_0.5.svg)](http://pkg.julialang.org/?pkg=ForwardDiff)
+[![ForwardDiff](http://pkg.julialang.org/badges/ForwardDiff_0.6.svg)](http://pkg.julialang.org/?pkg=ForwardDiff)
 
 **[Go To ForwardDiff's Documentation](http://www.juliadiff.org/ForwardDiff.jl/)**