Disable Travis CI

When JCaesar dropped all Boost fallbacks, this also meant that we
wouldn't be able to build on Ubuntu 12.04 LTS anymore (because that
comes with an ancient libstdc++ which has a broken <regex>). Until we
update the Travis config to use their newer container-based build
infrastructure, there's no point having them build everything when we
already know it'll fail.

.travis.yml

@@ -1,26 +0,0 @@
-language: cpp
-compiler: gcc
-
-# Build both GTK2 and GTK3 versions
-env:
-    - USE_GTK_VERSION=2
-    - USE_GTK_VERSION=3
-
-install:
-    - sudo apt-get -qq update
-    - >
-      sudo apt-get -qq install
-      build-essential cmake imagemagick
-      libboost-dev libboost-regex-dev
-      libfreetype6-dev
-      $([ "${USE_GTK_VERSION}" == 2 ] && echo 'libgtk2.0-dev libgtksourceview2.0-dev')
-      $([ "${USE_GTK_VERSION}" == 3 ] && echo 'libgtk-3-dev libgtksourceview-3.0-dev')
-      libjpeg-dev libpng-dev
-      libupnp-dev
-      libalut-dev libopenal-dev libogg-dev libvorbis-dev
-      libgl1-mesa-dev libglew-dev libxrandr-dev x11proto-core-dev
-      zlib1g-dev
-
-script:
-    - cmake $([ "${USE_GTK_VERSION}" == 3 ] && echo '-DUSE_GTK3:BOOL=TRUE') .
-    - make