Replaced lxml with html5lib
Fixed test which broke under html5lib

The test used HTML which wasn't valid HTML5. html5lib corrects these errors whereas lxml didn't so the result of the test is different.
Merge branch 'html5lib' of https://github.com/kaedroho/wagtail into kaedroho-html5lib
Update test_image_embed_is_rewritten to work on valid HTML input, to make it a more meaningful / representative test
add html5lib item to changelog + release notes
Merge branch 'kaedroho-html5lib'
Merge branch 'master' of github.com:torchbox/wagtail
remove libxml / libxslt from install scripts - not required now we've switched to html5lib
moved styleguide css to styleguide folder. added new help text styles
using best way of importing other sass
Merge pull request #486 from davecranwell/feature/help-messages

Added block help messages, suitable for use in any screen where information/instructions need to be conveyed to the user
rewrite documentation on binding pages to snippets (the linking model should be an inline child of the page, not a snippet itself)
Merge branch 'master' of github.com:torchbox/wagtail