Update .travis.yml to test on both julia-release and julia-nightlies

.travis.yml

@@ -1,18 +1,18 @@
 language: cpp
-compiler: 
-    - gcc
+compiler:
+  - clang
 notifications:
-    email: false
+  email: false
+env:
+  matrix: 
+    - JULIAVERSION="juliareleases" 
+    - JULIAVERSION="julianightlies" 
 before_install:
-    - sudo add-apt-repository ppa:staticfloat/julia-deps -y
-    - sudo add-apt-repository ppa:staticfloat/julianightlies -y
-    - sudo apt-get update -qq -y
-    - sudo apt-get install libpcre3-dev julia -y
-    - git config --global user.name "Dummy Travis User"
-    - git config --global user.email "[email protected]"
+  - sudo add-apt-repository ppa:staticfloat/julia-deps -y
+  - sudo add-apt-repository ppa:staticfloat/${JULIAVERSION} -y
+  - sudo apt-get update -qq -y
+  - sudo apt-get install libpcre3-dev julia -y
 script:
-    - julia -e 'versioninfo(); Pkg.init();'
-    - julia -e 'Pkg.add("NumericExtensions")'
-    - julia -e 'Pkg.add("StatsBase")'
-    - julia -e 'run(`ln -s $(pwd()) $(Pkg.dir())/Distributions`); Pkg.resolve()'
-    - julia ./run_tests.jl
+  - julia -e 'Pkg.init(); run(`ln -s $(pwd()) $(Pkg.dir("Distributions"))`); Pkg.pin("Distributions"); Pkg.resolve()'
+  - julia -e 'using Distributions; @assert isdefined(:Distributions); @assert typeof(Distributions) === Module'
+  - julia ./run_tests.jl