make docs: Added -pdf flag to latexmk

This is to avoid requiring all users to have a ~/.latexmkrc containing

    $pdf_mode = 1;

See the thread: "Error running make docs in peg-markdown"
http://groups.google.com/group/multimarkdown/browse_thread/thread/765c1c1e681ea069?hl=en
Merge pull request #90 from pmorch/master

Avoid: Error running make docs in peg-markdown
fix bug in OPML and Setext
fix path for latex
Remove tabs on blank line
make -> $(MAKE) make make (ha ha) more portable

For instance on OpenBSD:

$ MAKE=gmake make
Solaris compatibility
Merge pull request #101 from tangledhelix/solaris-compat

Solaris compatibility
Merge branch 'master' of git://github.com/nlegrand/peg-multimarkdown
Merge branch 'master' of github.com:fletcher/peg-multimarkdown

Conflicts:
	Makefile
Merge branch 'master' into development

Conflicts:
	Makefile
update to version 3.5
fix bug in LaTeX backslash output
fix bug in LaTeX backslash output (again?)
add some options for building for different architectures
fix typo in --help
update to 3.5.1
Correct spelling of Jalkut.
Merge pull request #103 from danielpunkass/patch-1

Correct spelling of Jalkut.
Makefile: re-use $PROGRAM in the target 'all'