.travis.yml: use container-based infrastructure

.travis.yml

@@ -1,9 +1,7 @@
+sudo: false
 language: c
+cache: apt
 compiler: clang
-before_script:
-    - sudo apt-get update
-    - sudo apt-get build-dep -qq xchat
-    - sudo apt-get install -qq libnotify-dev libproxy-dev libpci-dev libcanberra-dev monodevelop intltool
 script:
     - ./autogen.sh --enable-textfe --with-theme-manager --enable-static-analysis
     - make V=1 -j$(nproc)
@@ -14,3 +12,23 @@ notifications:
         on_success: change
 matrix:
      fast_finish: true
+addons:
+    apt:
+        packages:
+            - automake
+            - autoconf
+            - imagemagick
+            - intltool
+            - libcanberra-dev
+            - libdbus-glib-1-dev
+            - libglib2.0-dev
+            - libgtk2.0-dev
+            - libnotify-dev
+            - libpci-dev
+            - libperl-dev
+            - libproxy-dev
+            - libssl-dev
+            - libtool
+            - monodevelop
+            - mono-devel
+            - python-dev