Merge pull request #139 from Drup/map_sig

Simplify some Map and Set signatures.
Merge branch 'master' of github.com:ocaml/omd
fix: add a %! to flush warnings as they are issued

modified:   omd_utils.ml
feature: avoid printing \n\n if nothing follows

modified:   omd_backend.ml

might resolve https://github.com/ocaml/omd/issues/138#issuecomment-61417664
fix issue with HTML and newlines in Markdown output

Should fix https://github.com/ocaml/omd/issues/138#issuecomment-61417664

modified:   omd_backend.ml
modified:   omd_main.ml --> make sure the output ends with a `\n`, which is necessary following the modifications in omd_backend.ml
update version to 1.2.0

inaugurate options -w and -W

modified:   _oasis
update information regarding release 1.2.0

modified: README.md
fix: adapt to past changes in _oasis

modified:   Makefile
remove fewer `NL`s

modified: omd_representation.ml
fix: don't transform double newlines to single newlines

modified: omd_parser.ml
attempt to fix newlines policy

modified:   src/omd_backend.ml
fix: misjudged nature of HTML block in some contexts

should fix https://github.com/ocaml/omd/issues/142
avoid outputing too many consecutive empty lines

modified: omd_backend.ml
fix: HTML parsing issues

details:
 - fix: inline HTML tag followed by empty line or by nothing
   https://github.com/ocaml/omd/issues/144
 + add a few warnings, which cleans the code a little
 - fix: HTML comments followed by HTML tags
   https://github.com/ocaml/omd/issues/143

modified: omd_parser.ml
update version to 1.2.1

modified:   _oasis
modified:   README.md