Add support for python3 in liquid_tags/b64img.py
Add support for python3 in liquid_tags/b64img.py

The following error occured when used with python3

ImportError: No module named 'urllib2'

xsteadfastx/pelican-plugins,xsteadfastx/pelican-plugins,talha131/pelican-plugins,rlaboiss/pelican-plugins,danmackinlay/pelican-plugins,danmackinlay/pelican-plugins,mortada/pelican-plugins,mortada/pelican-plugins,UHBiocomputation/pelican-plugins,howthebodyworks/pelican-plugins,UHBiocomputation/pelican-plugins,danmackinlay/pelican-plugins,xsteadfastx/pelican-plugins,MarkusH/pelican-plugins,mortada/pelican-plugins,talha131/pelican-plugins,MarkusH/pelican-plugins,mikitex70/pelican-plugins,howthebodyworks/pelican-plugins,mikitex70/pelican-plugins,xsteadfastx/pelican-plugins,MarkusH/pelican-plugins,danmackinlay/pelican-plugins,rlaboiss/pelican-plugins,MarkusH/pelican-plugins,talha131/pelican-plugins,howthebodyworks/pelican-plugins,talha131/pelican-plugins,UHBiocomputation/pelican-plugins,mortada/pelican-plugins,rlaboiss/pelican-plugins,mortada/pelican-plugins,howthebodyworks/pelican-plugins,MarkusH/pelican-plugins,mikitex70/pelican-plugins,talha131/pelican-plugins,UHBiocomputation/pelican-plugins,rlaboiss/pelican-plugins,mikitex70/pelican-plugins