handling of additional_query_string in more_like_this

alert: it needs updated pyelasticsearch also
Merge remote-tracking branch 'upstream/master'

Conflicts:
	haystack/backends/elasticsearch_backend.py
666 issue from haystack
more facets
Merge remote-tracking branch 'upstream/master'

Conflicts:
	haystack/backends/elasticsearch_backend.py
Merge remote-tracking branch 'upstream/master'
bounding box and within spatial search fixed
spatial settings back to before
Fixed the docs on debugging to cover v2. Thanks to eltesttox for the report.
Because Windows.
Merge branch 'master', remote-tracking branch 'toastdriven/master' into bounding_box

Conflicts:
	haystack/utils/geo.py