update travis: java 8, capnp 0.5.1

.travis.yml

@@ -1,20 +1,17 @@
 language: java
 jdk:
+  - oraclejdk8
+  - openjdk8
   - oraclejdk7
   - openjdk7
-  - openjdk6
 before_install:
   - yes | sudo add-apt-repository ppa:ubuntu-toolchain-r/test
   - sudo apt-get update
 install:
-  - sudo apt-get install g++-4.8 gcc-4.8 git
-  - git clone https://github.com/kentonv/capnproto.git
-  - export CC=gcc-4.8
-  - export CXX=g++-4.8
-  - cd capnproto/c++
-  - ./setup-autotools.sh
-  - autoreconf -i
-  - ./configure && make -j5 && sudo make install && cd ../..
+  - sudo apt-get install g++-4.8 gcc-4.8
+  - curl -O https://capnproto.org/capnproto-c++-0.5.1.tar.gz
+  - tar zxf capnproto-c++-0.5.1.tar.gz
+  - cd capnproto-c++-0.5.1 && ./configure && make -j5 && sudo make install && cd ..
 script:
   - make CXX=g++-4.8 CXX_FLAGS="-std=c++11 -I/usr/local/include -L/usr/local/lib -lcapnp -lkj"
   - make addressbook