Close file handle when nodepath arg to ctable.fromhdf5 is incorrect.

Close the tables file before re-raising the exception that occurs during
node retrieval to prevent leaking file handles.

Catch all exceptions so that NoSuchNodeErrors, ValueErrors and other
errors are all handled.
pep8 all the things
adding initial travis config
install cython in a version appropriate for bcolz
pep8 the tests and some more bits and bobs
function to get the current git description
print the git info if available
move test_all.py -> all.py fixes #44
adding .gitignore file
adding mailmap for git shortlog -s -n
add a compatability layer for subprocess.check_output on py2.6
fix Cython version import
fix include of definitions.pxd
remove version spec in travis config
fix typo
Numpy sum will overflow if N too large
force larger output dtype to avoid overflow on 32 bit
fix typos in RELEASING.rst
fix typo in ANNOUNCE.rst
fix typo