display error message to minibuffer when goto next/prev error.
fix for https://github.com/kazu-yamamoto/ghc-mod/pull/206#issuecomment-39628265
Merge pull request #206 from notogawa/display-minibuf

display error message to minibuffer when goto next/prev error.
moving a variable to a proper place.
fix filepath handling in windows
Merge pull request #207 from Kiripon/windowsFilePathHandling

fix filepath handling in windows
comment.