adding a test stub
use Py_ssize_t in decompress_ptr

Since we are using 's#' here, we don't need to check if cbytes is less than
zero, since the length of the corresponding python bytesoby can never be less
than zero.

Adresses #26
fix return type of decompress_ptr

Adresses #28 and decompress_ptr now returns the number of bytes written to the
buffer.
expose returning nbytes from decompress_ptr to toplevel
Enjoy data!
add blosc import to allow running doctests from nosetests
run unittests similarly to doctests
more elaborate instructions for running the tests
testing exceptions raises during compression
testing exceptions raises during compression_ptr
remove spurious line in docstring
testing exceptions raised during decompress
testing exceptions raised during decompress_ptr
refactor the test code a little
test exceptions raised when packing an array
test exception raised by set_nthreads
check exception raised during unpack_array
Merge pull request #32 from esc/test_suite

growing a test suite
Merge branch 'fix_decompress_ptr' of github.com:esc/python-blosc into esc-fix_decompress_ptr
Merge pull request #34 from esc/branding

some essential branding for this product