add rc/markdown.kak
add rc/css.kak
add rc/html.kak
add rc/scala.kak
add rc/haskell.kak
add rc/lisp.kak
add rc/clojure.kak
make.kak: Support fatal errors in errnext / errprev
Rewrite real_path, try to find an existing directory in the given path

Never throw, return the given filename in the worst case.
Merge support for some additional languages from alexherbo2

 * alexherbo2/lisp-rc
 * alexherbo2/clojure-rc
 * alexherbo2/haskell-rc
 * alexherbo2/scala-rc
 * alexherbo2/markdown-rc
 * alexherbo2/css-rc
 * alexherbo2/html-rc