Prevent mayavi figures from popping up
Prevent mayavi figures from popping up

when generating the doc. Fix #56.

sphinx-gallery/sphinx-gallery,lesteve/sphinx-gallery,sphinx-gallery/sphinx-gallery,Eric89GXL/sphinx-gallery,Titan-C/sphinx-gallery,Titan-C/sphinx-gallery,Eric89GXL/sphinx-gallery,lesteve/sphinx-gallery