MAINT compatibility layer for textwrap.indent for python 2
MAINT compatibility layer for textwrap.indent for python 2

and fix missing argument in indent function

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