removing fast/slow code.
the first step to make ghc-mod independent from GHC's version.
cleaning up the logger.
new APIs.
adding ghc-modi.
"debug" displyas a root dir.
fixing strange usage of defstruct.
adding ghc-check.el finally.

Still developping.
empty line.
ghc-check-display-errors.
ghc-goto-next-error.
fixing sentinel.
ghc-mod root.
ok/ng hack.
make ghc-modi robust.
layout.
hilit for insert-template.
removing ghc-flymake-jump.
adding todo.
Errors does not have "Error" prefix.