Merge branch 'master' into 'master'

Upgrade indexd_gzip version

See merge request !12

requirements.txt

 six>=1.10.0,<2.0
 numpy>=1.11.1,<2.0
 nibabel>=2.1,<3.0
-indexed_gzip>=0.3.2,<0.4
+indexed_gzip>=0.3.3,<0.4
 wxPython>=3.0.2.0,<=4.0