Fix test files.
add tox configuration and ignore vim swap files.
build magic binding with cffi instead of cython.
ignore useless files.
update the usage of wrapper.
remove the cython sources.
fix up the missing data problem.
add missing patch file into manifest
add test data into manifest
fix up the location of magic.mgc
fix up the wrong length of buffer.
migrate test cases into contextmanager-based api.