Travis: Build binary wheels

[bauerj]

This will build manylinux2010 compatible binary wheels for Python 2.7, 3.4, 3.5, 3.6 and 3.7. Manylinux2010 binaries will work on almost any Linux-based system with a C library from 2010 or newer without having to install any dependencies.

The official manylinux2010 Docker image, which is based on ancient Centos 6 is used to compile rocksdb and python-rocksdb.

In order to automatically upload new releases to PyPi, you should make some changes before merging:

• Set TWINE_USERNAME in the .travis.yml to a username that has access to python-rocksdb on PyPi.
• Using the Travis-CI Web Interface, add a hidden TWINE_PASSWORD variable for that user: https://docs.travis-ci.com/user/environment-variables/#defining-variables-in-repository-settings

Once this is done, binary wheels for new releases will be automatically uploaded after a new tag is pushed and the tests succeed.

Let me know if you have any questions.

-- Closes: #30

[bauerj]

Here are a few wheels to test. Please report whether they work:

• Python 3.5: https://bauerj.eu/wheelhouse/python_rocksdb-0.7.0-cp35-cp35m-manylinux2010_x86_64.whl
• Python 3.6: https://bauerj.eu/wheelhouse/python_rocksdb-0.7.0-cp36-cp36m-manylinux2010_x86_64.whl
• Python 3.7: https://bauerj.eu/wheelhouse/python_rocksdb-0.7.0-cp37-cp37m-manylinux2010_x86_64.whl

[bauerj]

@twmht Do you have questions regarding this PR? 😊

[bauerj]

@twmht Maybe you have missed this, could you take a look at this?

[eterna2]

Would be nice if this can be merged in.

[SuBPaR42]

@bauerj - any chance for a new version for python 3.9 since that is default in Debian11?