packaging: add make target for linux wheels Having linux wheels is going to helps system without compiler or python-dev plus speed up the installation for everyone. I followed the manylinux example repository https://github.com/pypa/python-manylinux-demo to add a make target (build-linux-wheels) using official docker image to build python 2 linux wheels for mercurial. It generates Python 2.6 and Python 2.7 for both 32 and 64 bits architectures. I had to blacklist several test cases for various reasons: * test-convert-git.t and test-subrepo-git.t because of the git version * test-patchbomb-tls.t because of warning using tls 1.0 It's likely because the docker image is based on centos 5.0 and openssl is outdated.