Fix inline doc for Rakefile content

The previous docs would set the `require 'quarto/tasks'` to be inline but because the code was set to be displayed as `ruby` code and no newline was present before the code block, the `ruby` processing command was displayed as text.

This changes the docs from saying `ruby require 'quarto/tasks'` to `require 'quarto/tasks'`

As a result, the display code is no longer inline, but it is syntax highlighted.
Merge pull request #14 from saturnflyer/master

Fix inline doc for Rakefile content
Nobody likes a project with failing tests...
Ensure vendor/org dir exists before symlinking orgmode into it.
Merge branch 'master' of github.com:avdi/quarto
Fix a failing test case with empty markdown input docs.

Probably as a result of an upgrade to a new Ubuntu version, the HTML
versions of blank Markdown docs started containing a boilerplate BODY
containing just an empty P tag. Added handling for this case.
Fix rake dependency in gemspec

Error was (in ruby 2.1.0):
    quarto at /Users/brad/dev/avdi/quarto did not have a valid gemspec.
    This prevents bundler from installing bins or native extensions, but
    that may not affect its functionality.
    The validation message from Rubygems was:
      duplicate dependency on rake (~> 10.0, development), (~> 10.0) use:
          add_runtime_dependency 'rake', '~> 10.0', '~> 10.0'
Do not remove orgmode tarball in clean

  I was surprised to see the tarball re-download after a `rake clean`.
  To me, removing that file belongs in `rake clobber`.

  Also, I don't have wget on my machine, so here's a fallback to curl.
Merge pull request #24 from listrophy/fix_rake_in_gemspec

Fix rake dependency in gemspec
Update README.md
Add pdf_samples plugin.
Update to latest test-construct gem.

...and a whole bunch of other stuff. Boy, I hate it when I leave a
bunch of changes lying around and then come back and find them months
later. Bad Avdi! Bad!
Merge branch 'master' of github.com:avdi/quarto
Correct test_construct dependency.
Move kindlegen-generated KF8 file into subdirectory.

Because Amazon are poo-poo heads.
Add calibre_mobi plugin for mobi/KF8 generation.

Because Amazon are poo-poo heads.
Add missing dependency between spine and section files.
First cut at site-building functionality.
More template features.
Template madness! partials, layouts, etc.