Python打包的时候默认是将.py文件全部打包
但是有时候我们需要把non-py文件打包，比如说json文件
有个机制可以让我们做到：
The mechanism that provides this is the MANIFEST.in file. This is relatively quite simple: MANIFEST.in is really just a list of relative file paths specifying files or globs to include.:
include README.rst
include docs/*.txt
include funniest/data.json
为了让上面的能够work，我们需要在setup.py里面讲include_package_data=True添加上
In order for these files to be copied at install time to the package’s folder inside site-packages, you’ll need to supply include_package_data=True to the setup() function.
参考：http://python-packaging.readthedocs.io/en/latest/non-code-files.html
