Add support/tests for Redcarpet 3.0.0 features
- :underline
- :highlight
- :disable_indented_code_blocks

Fix support for
- :link_attributes
- :filter_html

separate Redcarpet extensions from renderer options, add specs for missing renderer options

add specs for the missing/new redcarpet extensions, [ :lax_spacing, :underline, :highlight, :quote, :disable_indented_code_blocks, :footnotes ]

fix link_attributes option for Redcarpet

patch Tilt's reverse option aliases (they were there for RC1)

adjust test data for Redcarpet toc_data to match the current way it renders in 3.0

revert tests that aren't in redcarpet 3.0.0

add a cucumber exempt tag for mri-1.8.x

move redcarpet 3 specific extensions to a separate scenario filtered by the no18 tag
Merge pull request #1001 from stevenosloan/redcarpet_3

Add tests for Redcarpet 3.0.0 options, fix the few that didn't pass
prep
Demonstrate issue with directory indexes and spaces in paths

References #961
Make an effort to handle spaces in filenames in a way that url_for can handle.
Loosen kramdown dependency
Normalize paths in the cleaning queue using realpath in order to avoid complicated symlink problems.
Use our magic linking functions from Kramdown, just like we do with Redcarpet. Fixes #999
Merge pull request #999 from bhollis/kramdown

Default markdown renderer (kramdown) does not use Middleman Sitemap
Look for assets using url_for before falling back to the "images" directory
Do not cache generated redirect index file.

Returning visitors to site were being redirected to the old page because their browser was caching the index page which was pointing to the previously URL.
Merge pull request #1017 from bhollis/url_for

Look for assets using url_for before falling back to the "images" directory
Merge pull request #1019 from tavon/master

Do not cache generated redirect index file.
Add test against URL fragments for asset hashes
Merge pull request #1027 from metalabdesign/asset_hash_url_fragment_test

Add test against URL fragments for asset hashes
temp disable jruby tests
adjust some markdown tests
force latest kramdown
Doc: topic branch link fix
Merge pull request #1042 from sDaniel/topic_branch_doc_linkfix

Doc: Topic branch link fix