set text as default lexer for unspecified language blocks
remove accidental commit
add support for new capabilities provided by Redcarpet 3.0
new Commands
syntax change

add primitive support for syntax coloring other languages in fenced
blocks based on language tag
preview output

add Redcarpet to the title on the output window
backtick pairing

Disable backtick pairing for now. It is making creation of fenced code
blocks (```) a little tedious. Need to look into fixing this better.
help cleanup

needs to be rewritten with all the new redcarpet stuff.