Try to be consistent across the names and the code
Redcarpet v3.1.0
Properly define the header_anchor helper function

Prevents all the various segfaults we've seen since 3.1.0

Fixes #349
Update CHANGELOG for 3.1.1 release
Update the gemspec for the 3.1.1 release
Bump module version
Redcarpet v3.1.1
Remove the allowed failure for Rubinius

Since commit 7f82fb59945, everything is green! :green_heart:
Added 'Get started quickly' section
Remove a compiler warning

In 7b48ac95, the bufcstr prototype has been changed. This lead to a
warning since bufgrow is meant to change the allocated size to the given
buffer but the latter is a const.
Add a note about callback overriding [ci skip]

To avoid unexpected outputs, the callback should return a HTML element
with a level that matches the level of the overwritten callback.

Refs #336
Strip image links in StripDown renderer
Merge pull request #356 from MrZYX/stripdown_images

Let StripDown handle image tags
Merge pull request #355 from vmg/buffer-warning

Remove a compiler warning
Merge pull request #353 from evolve2k/patch-1

Added 'Get started quickly' section to README [ci skip]
Follow up to #353 [ci skip]

Improve a bit the README and use 1.9 hash syntax in code examples
Change MKDEXT_NO_INTRA_EMPHASIS to not start after alphanumerics

No behavior should change if the NO_INTRA_EMPHASIS flag is not set.
With it
set, the following behavior changes should be seen:  (The parentheses
in the
following examples can be replaced by any non-alphanumeric character.)

- "(_italics_)" is italic
- "this(_is_)weird" italicizes the "is"

We were already checking for non-alphanumerics  on the closing boundary;
that is, "_this_()" would have rendered as italicized even though the
closing
underscore wasn't followed by a space. This commit just brings the same
behavior to the opening underscore.
Update README.markdown
Merge pull request #362 from nemesis/patch-1

Update README.markdown [ci skip]
Merge pull request #361 from bigjason/intra-emph-refine

Change MKDEXT_NO_INTRA_EMPHASIS to not start after alphanumerics