Redo after corrupted codebase.
Added serve option as a post processor.
Deleted writer version of --serve.
Capturing Keyboard interrupt.
Adding --to slides --post serve example in help.
Deleted empty spaces.
Added webbroser to auto open the slideshow.
Made open_in_browser configurable.
Merge pull request #3780 from damianavila/reveal_writer

Added serving the output directory if html-based format are selected.