* HTML output has gotten a fresh, more modern look. It makes
better use of CSS and uses fewer bitmaps.
* Added page outline navigation panel to the HTML output
* Added new layout option: full height side bar + navigation tabs
* Improved flexibility of `\cite` command
* Support for Plus sign code fence directives - GitHub flavor
OBS-URL: https://build.opensuse.org/package/show/devel:tools/doxygen?expand=0&rev=219
