Update .travis.yml to container based travis

.travis.yml

@@ -1,20 +1,41 @@
+sudo: false
+
 matrix:
   include:
     - env: GHCVER=7.8.4 CABALVER=1.18 STACK_YAML=stack-7.8.yaml
+      addons:
+        apt:
+          sources:
+          - hvr-ghc
+          packages:
+          - ghc-7.8.4
+          - cabal-install-1.18
     - env: GHCVER=7.10.1 CABALVER=1.22 STACK_YAML=stack.yaml
-    - env: GHCVER=7.10.2 CABALVER=1.22 STACK_YAML=stack.yaml
+      addons:
+        apt:
+          sources:
+          - hvr-ghc
+          packages:
+          - ghc-7.10.1
+          - cabal-install-1.22
+
+# Disabled until travis allows the ghc-7.10.2 package
+#
+#    - env: GHCVER=7.10.2 CABALVER=1.22 STACK_YAML=stack.yaml
+#      addons:
+#        apt:
+#          sources:
+#          - hvr-ghc
+#          packages:
+#          - ghc-7.10.2
+#          - cabal-install-1.22
 
 # Disabled until haddock-api supports it
 #    - env: GHCVER=head CABALVER=1.22 STACK_YAML=stack.yaml
 #  allow_failures:
 #    - env: GHCVER=head STACK_YAML=stack.yaml
 
 before_install:
-  # ghc
-  - travis_retry sudo add-apt-repository -y ppa:hvr/ghc
-  - travis_retry sudo apt-get update
-  - travis_retry sudo apt-get install cabal-install-$CABALVER ghc-$GHCVER
-  # stack
   - mkdir -p ~/.local/bin
   - export PATH=~/.local/bin:/opt/ghc/$GHCVER/bin:/opt/cabal/$CABALVER/bin:$PATH
   - travis_retry curl -L https://github.com/commercialhaskell/stack/releases/download/v0.1.2.0/stack-0.1.2.0-x86_64-linux.gz | gunzip > ~/.local/bin/stack