Fix use-after-close lazy IO bug

Make `getPrologue` force `parseParas dflags str` before returning. Without this,
it will attempt to read from the file after it is closed, with unspecified and
generally bad results.

Signed-off-by: David Feuer <David.Feuer@gmail.com>
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Add an .arcconfig file.

Signed-off-by: Austin Seipp <austin@well-typed.com>
Add .arclint file.

Signed-off-by: Austin Seipp <austin@well-typed.com>
Experimental support for collapsable headers

(cherry picked from commit e2ed3b9d8dfab09f1b1861dbc8e74f08e137ebcc)
Collapse user-defined section by default (re #335)
reflect ForeignType constructore removal

Reviewers: austin

Reviewed By: austin

Differential Revision: https://phabricator.haskell.org/D358
Remove overlapping pattern match

Signed-off-by: Austin Seipp <aseipp@pobox.com>
Support for PartialTypeSignatures