[#708] Fix render_markdown() helper function
[#708] Switch over to use markdown_extract() not misc.py

Conflicts:

	ckan/controllers/group.py
[#708] Fix tests
[#708] Get markdown_extract() to use RE_MD_HTML_TAGS
[#708] Minor refactor
[#708] Clean up code, fix comment, remove obvious comment
[#708] Add more tests to link detection tests
[#776] Show organization search facets by default

Show faceting by organization by default on the dataset search page.
Fixes #776.
Merge branch 'release-v2.0' of github.com:okfn/ckan into release-v2.0