Renamed Twig/Extension to Twig/Extensions

Signed-off-by: Parth Sarin <parthsarin@gmail.com>
Various fixes.

-- Slugging of URLs for Individual Blogs instituted.
-- Latest comments in sidebar instituted.
-- Fixed Namespace problem for custom Twig Extension in services.yml.

Signed-off-by: Parth Sarin <parthsarin@gmail.com>
Merge branch 'refs/heads/develop'
Changed .gitignore file to exclude phpunit.xml
Merge branch 'refs/heads/develop'