Add Travis-CI cache directories.

Author: proofit404

.travis.yml

@@ -1,16 +1,21 @@
 language: emacs-lisp
-
+cache:
+  directories:
+    - $HOME/.cache/pip
+    - $HOME/.pyenv
+    - $HOME/.evm
+    - $HOME/.cask
+    - $TRAVIS_BUILD_DIR/.cask
+    - $TRAVIS_BUILD_DIR/.tox
+    - /usr/local/evm
 env:
   global:
     - PATH=$HOME/.evm/bin:$HOME/.cask/bin:$PATH
-
 before_install:
   - sudo apt-add-repository -y ppa:ansible/ansible
   - sudo apt-get update
   - sudo apt-get install -y ansible
-
 install:
   - ./travis.sh
-
 script:
   - ./ert.sh