Adding new theme for spa plugin
Copying some template files from bootstrap-jinja theme into spa-jinja (commit 6c31636)
Copying two templates from bootstrap3-jinja theme into spa-jinja (commit 6c31636)
Move post_header.tmpl to partials/ subdir
Extracted post content block into partials/post.tmpl
Copying comments_helper*.tmpl and post_helper.tmpl from base-jinja theme (commit 6c31636)
Exported head template in its own partial and changed it to work get_post_data
Removed unused "with context" imports
Removed invalid template code
Adapted post template code to use data from get_post_data()