Improve documentation and packaging

This release include various minor improvements on packaging and documentation, including

• Enhance CMake errors reporting when compile from source (GH-112)
• Include the full test suite to the source distribution (2e39a68)
• Better distinguish read-only/read-write/write-only properties in docstrings (GH-102)
• Correct multiple-value return type (GH-107)

And other esthetic change in docstring formatting.