3.0.0 (in development)
Remove dumb methods. Give others better names.

The following methods were renamed:

  clean -> fragment
  clean_document -> document
  clean_node! -> node!

The following methods were deleted, because they were silly:

  clean!
  clean_document!
Merge branch 'dev-2.1.0' into dev-3.0.0
Use the Gumbo HTML5 parser instead of Nokogiri.

This change is EXPERIMENTAL and should not yet be used in production
environments or with untrusted input!

Note that quite a few tests currently fail due to parsing differences
between the Nokogiri parser and Gumbo.
Merge branch 'dev-2.1.0' into dev-3.0.0
Merge branch 'dev-2.1.0' into dev-3.0.0
Merge branch 'master' into dev-3.0.0

Conflicts:
	HISTORY.md
Convert :whitespace_elements into a Hash.

This will let developers to configure Sanitize to specify the
replacements for :whitespace_elements found in the input. Previously,
developers couldn't specify the text to be inserted before and after
the :whitespace_elements.

- updated :whitespace_elements to be a Hash rather than an Array.
- updated CleanElement#call to use appropriate replacements for the
  element found instead of hardcoded space (' ').
- made sure existing tests were not broken and added new tests for the
  functionality added by overriding replacement values for tags.
- updated README to reflect these changes.

NOTE: Changes are backwards compatible. Code will detect Array types
and will convert them into the new Hash format.
Update history.
Merge branch 'master' into dev-2.2.0
Merge branch 'dev-2.2.0' into dev-3.0.0

Conflicts:
	HISTORY.md
Merge branch 'dev-3.0.0' into gumbo
Move REGEX_DATA_ATTR and REGEX_PROTOCOL into the CleanElement transformer.
Require Nokogumbo ~> 1.1.5.
Require Minitest ~> 5.3.4.
Add a history entry about Gumbo.
Mention Gumbo in the readme.
Remove :output and :output_encoding.
Use require_relative.
Move sanitize/config.rb to sanitize/config/default.rb.

For consistency.