Fix #80

Searching for a non-existent editor's pick now displays the correct not
found message.
Merge pull request #365 from mope/80-fix-editors-picks-search

Fix #80
Update CONTRIBUTORS.rst
Embeds: Fixed crash when no HTML field is sent back from the embed provider
Merge pull request #369 from kaedroho/embeds-fix-2

Embeds: Fixed crash when no HTML field is sent back from the embed provider
Move normalise_query_string into wagtailsearch utils and use it in the backends
Merge pull request #370 from kaedroho/search-fix

Move normalise_query_string into wagtailsearch.utils and use it in the backends
fixes issue #373
Merge pull request #374 from davecranwell/fix/373

fixes issue #373
Changelog for #374
Changelog for #369