odf.c: strip a trailing space

This fixes the gcc warning:

  odf.c: In function Î÷Îõprint_odf_headerÎéÎ÷:
  odf.c:102:64: warning: backslash and newline separated by space
markdown_lib.c: use %p to print pointers
Merge pull request #9 from rctay/rc/gcc-wall

minor fixes for compiler warnings
Updated README instructions for mingw compile.
Disallow blank space between [label] and ( in inline link.

The official markdown syntax description says that a blank
space is allowed between ] and [ in a reference style link,
but it does not say this for an inline link; instead, it says
that the ( must be immediately after the ].  This interpretation
is confirmed by the behavior of Markdown.pl.

This change brings peg-markdown into agreement with Markdown.pl,
PHP markdown, and pandoc.  Note that some markdown implementations
(discount, sundown) do allow the space.  Though something can be
said in favor of allowing the space, it seems best to go with
the spec to resolve such disagreements.

In addition, with short reference style links, it is easy to
do something like

    [my link] (word)

    [my link]: /url

which we wouldn't want to parse as an inline link.
Updated glib download link.  Closes #11.
New extension: strike through with two tildes
require space between "#" and heading text
require space between "#" and heading text
disable strike-through extension by default
Merge branch 'strike-extension'
Merge branch 'atx-header-requires-space'
New extension: autolink for converting bare URLs to links
fix problems with explicit links and autolink extension
New extension: hard wrap

Insert linebreaks inside paragraphs where the origin Markdown document
had newlines (by default, Markdown ignores these newlines).

EXT_HARD_WRAP
--hardwrap
support for media embedding

New syntax for embedding audio files:

    ~[Audio file title]( http://url-of/first-source.mp3
                         http://url-of/second-source.ogg )

This is converted to:

    <audio controls="true">
      <source src="http://url-of/first-source.mp3 />
      <source src="http://url-of/second-source.ogg />
    </audio>
    <div class="audio-file-title">
      Audio file title
    </div>

Mnemonic: "~" looks a bit like a sine wave form.

~~~~

New syntax for embedding video files:

    %[Video file title]( http://url-of/first-source.mp4
                         http://url-of/second-source.ogv )

This is converted to:

    <video controls="true">
      <source src="http://url-of/first-source.mp4 />
      <source src="http://url-of/second-source.ogv />
    </audio>
    <div class="video-file-title">
      Video file title
    </div>

Mnemonic: "%" looks a bit like a position indicator.
output second source only if provided
Merge branch 'master' into audio-embedding

Conflicts:
	README.markdown
	markdown.c
	markdown_lib.h
	markdown_parser.leg
recognise media syntax only if EXT_MEDIA is set
Merge branch 'master' into audio-embedding