doc: a few fixes

[adrientetar]

• Closes Rustdoc: monospaced font appears too large on a Retina display #10330
• Improves on doc: CodeMirror should ignore 'static/'self #9873
• Adds favicon for tutorial files

[adrientetar]

@alexcrichton How does it looks?
I used http://stackoverflow.com/a/649462.

[alexcrichton]

It's not really necessary to use DEFINE, you can just use a normal variable like PANDOC_OPTS := -flag a -flag b etc.

Also, it still seems like there's quite a few flags shared among all the rules:

--to
--section-divs
--standalone
--toc
--number-sections
--from
--css

etc.

[adrientetar]

@alexcrichton Long lines but oh well. So I made flags for each filetype.

[alexcrichton]

You can interpolate makefile variables into others, so you can have a scheme like:

BASE_PANDOC_OPTS := -a -b -c
TEX_OPTS = $(BASE_PANDOC_OPTS) -d -e -f
HTML_OPTS = $(BASE_PANDOC_OPTS) -h -i -j

[adrientetar]

@alexcrichton Done.

What's the difference between := and =?
EDIT: http://www.gnu.org/software/make/manual/html_node/Overriding.html#Overriding

[alexcrichton]

There is a difference in makefile land, but to me it's just magical. I normally just pick the one that works and/or doesn't spit out errors.

That being said, the actual difference is that := is expanded when it's defined, but = is expanded when it's used. http://www.gnu.org/software/make/manual/make.html#Flavors probably has more information than I could give anyway :)

[adrientetar]

@alexcrichton Can you r+ again? I just updated a reference for #10423. ty!

[adrientetar]

@alexcrichton Nasty bitrot.

[adrientetar]

@alexcrichton Fixed.