NF: __reduce__ and __repr__ in VolumeBasedSurface
BF: converting from iso-8859-15 into utf-8 for having Pólya

I believe that this is what was causing coversall to fail
Thanks Илья Барышев for the support
ENH: respect externals check for pprocess + tune up exception msg

Otherwise it becomes difficult to disable pprocess for the purpose of debugging
without uninstalling it or tricking it via PYTHONPATH etc
ENH: introduce internal _strid to unify appearance of ids (Close #116)
NF: equality test for VolumeBasedSurface (Close #114)
Merge pull request #110 from nno/master

NIML hstack support + refactoring of Kohonen SOM + flat_surf plots + kitchen sink ;)
BF(TST): fixed test_winner and added it to the test battery
ENH: Guard against nibabels fragility under valgrind - disable it if crashes upon import
BF: numpy 1.7.x compatibility -- use frombuffer on ctype'd array instead of asarray

Issue: https://github.com/numpy/numpy/issues/3406
BF: numpy 1.7.x compatibility -- read-only is now ValueError (not
RuntimeError) (Close #115)
ENH: use travis_retry to try avoid networking problems while accessing nd repo