travis: drop all use of sudo and root-owned directories

From
http://docs.travis-ci.com/user/migrating-from-legacy/

.travis.yml

@@ -13,9 +13,9 @@ addons:
 sudo: false
 script:
   - autoreconf
-  - ./configure
+  - ./configure --prefix=$HOME/prefix
   - make -j2
-  - sudo make install
+  - make install
   - make test SHOW_INTERACTIVE_LOG=1
 notifications:
   irc: