try travis pypy3

.travis.yml

@@ -4,7 +4,7 @@ python:
 - '2.7'
 - '3.5'
 - '3.6'
-- 'pypy3'
+- 'pypy3.5-5.8.0'
 env:
   global:
   - LD_LIBRARY_PATH=./libsecp256k1_ext/.libs
@@ -56,11 +56,6 @@ addons:
     - libffi-dev
     - libgmp-dev
 before_install:
-- cd $HOME
-- "if [[ ! -e ./bin ]]; then mkdir bin; fi"
-- export PATH=$HOME/bin:$PATH
-- "if [[ $TRAVIS_PYTHON_VERSION == 'pypy3' ]]; then deactivate && wget https://bitbucket.org/squeaky/portable-pypy/downloads/pypy3.5-5.8-beta-linux_x86_64-portable.tar.bz2 && tar -jxvf pypy3.5-5.8-beta-linux_x86_64-portable.tar.bz2 && echo 'Setting up aliases...' && cd pypy3.5-5.8-beta-linux_x86_64-portable/bin/ && export PATH=$PWD:$PATH && ln -s pypy3 python && echo 'Setting up pip...' && ./pypy3 -m ensurepip && ln -s pip3 pip ; fi"
-- cd $TRAVIS_BUILD_DIR
 - chmod +x .travis/prepare_windows_build.sh .travis/build_windows_wheels.sh
 - .travis/prepare_windows_build.sh
 - source .travis/install.sh