Fix Travis build, again.

.travis.yml

@@ -1,15 +1,16 @@
 language: cpp
+compiler: gcc
 
-compiler:
- - gcc
+dist: trusty
+sudo: required
 
 env:
  - QT4_BUILD=OFF
 
 before_install:
- - sudo add-apt-repository --yes ppa:beineri/opt-qt591-trusty
+ - sudo add-apt-repository --yes ppa:ubuntu-toolchain-r/test
+ - sudo add-apt-repository --yes ppa:ubuntu-sdk-team/ppa
  - sudo apt-get update -qq
- - sudo apt-get install -qq qt59base
 
 script:
  - mkdir build