ENH: make VolumeMaskDictionary available through the suite
Merge branch 'master' into _tent/surfing
BF: when merging voxel selection results (e.g. from different threads from pprocess), ensure that the datatypes of aux (i.e. misc) attributes match - even if some of the results that are merged have no keys associated with them. Addresses issue #162
RF: use np.asanyarray for simpler code
RF: simplified code as suggested by yoh in PR #164
Merge pull request #164 from nno/_tent/surfing

more tests in surfing + better PY3k compatibility