isinstance(x, (str, native_str)) everywhere

see #712
travis ping
Merge pull request #714 from mbyt/isinstance

Py3k: isinstance(x, (str, native_str)) everywhere
smart calculation of nfft in Trace.remove_response

in case large primes are encountered in nfft factorization (which makes
the computation take forever) we simply switch to using the next power
of 2, which is not the fastest possibility but has robust computation
time.
exclude obspy/lib/*.py from flake8 code check

closes #716
Merge branch 'releases'
nfft: try to avoid going up to power of 2, try out some slightly larger
values before that
nfft: avoid problems with large primes in seisSim, too

changelog
nfft calculation: more tries to find good nfft number, computation time
of factorization is negligible compared to fft/evalresp/ifft

(e.g. for a trace with 1e7 points: factorization is <1ms but response
calculation is >1min)
fix previous commits
Merge remote-tracking branch 'megies/smart_nfft' into releases (see #715)
Merge branch 'releases' (see #715)
fix exclusion of obspy/lib in code formatting test

exclusion patterns with fnmatch are not customizable enough for the
intended check. regex would work but then we have to allow for different
dir separator on windows/unix in regex check..
Merge remote-tracking branch 'upstream/releases'
fdsn: avoid hiding timeout errors from the user, raise all exceptions
(unless "debug=True"), see #717
fdsn: make it possible to specify timeout for Client (see #717)
Merge remote-tracking branch 'upstream/releases'

Conflicts:
	obspy/fdsn/client.py
fix (futurize) merge of changes in 707647c
minor py2/3 fix
Update inventory.py

Bugfix in *get_response()*