* reuse html builder
* rename videos extension to youtube_frame
* remove HTML body max/min parameters
* remove reference to release number in HTML title
* Use dirhtml as default builder for readthedocs (clean URLs)
* The configuration variables are now sorted with respect to the Sphinx
documentation
* Remove useless comments in conf.py
* Add new comments for each section, following Sphinx documentation
order
* The code corresponding to videos have been moved from config to a
dedicated extension.
* Use proper HTML theme options
* Exclude all files starting with `.`, `_` (sphinx convention)
* Use OpenSearch
