Fix Travis CI build

tcell build is commented out as it doesn't reliably respond to tmux
send-keys.

.travis.yml

@@ -4,16 +4,13 @@ matrix:
     - env: TAGS=
       rvm: 2.3.3
 #   - env: TAGS=tcell
-#     rvm: 2.2.0
+#     rvm: 2.3.3
 
 install:
-- sudo apt-get update
-- sudo apt-get install -y libncurses-dev lib32ncurses5-dev libgpm-dev
 - sudo add-apt-repository -y ppa:pi-rho/dev
 - sudo apt-add-repository -y ppa:fish-shell/release-2
 - sudo apt-get update
-- sudo apt-get install -y tmux=1.9a-1~ppa1~p
-- sudo apt-get install -y zsh fish
+- sudo apt-get install -y tmux zsh fish
 
 script: |
   make test install &&