[#226] Implemented generic text highlighter for JSON, XML and plain text. Deleted jsonpreview.
unified indentation
[#226] Rename text highligher extension to text preview
[#226] Add missing license for highlight.js
[#226] Use github style
[#226] Make jsonp preview more resistant, add missing converter to jsonp
[#226] Rename text preview tests, add test for whether css is present
[#226] Make it easier to add new formats to the json/xml/text preview
Merge remote-tracking branch 'okfn/master' into 226-text-highlighting

Conflicts:
	ckanext/textpreview/tests/test_preview.py
[#764] Install vdm from the Python Package Index

Makes easier to install CKAN on offline environments
Merge branch 'master' into 226-text-highlighting

Conflicts:
	ckan/config/deployment.ini_tmpl
[#226] Fix merge
[#226] Preview geojson with json preview
[#226] Make ajax request for preview async to prevent the request from blocking the ui
[#226] Show original error message, if possible, instead of a not very helpful default message.
[#905] Validate datastore actions against a schema
[#905] Do not raise 500 if the wrong type is passed to datastore_create or datastore_upsert
[#905] CLean up import, capitalized constants
[#905] Add missing schema file. Thanks @tobes
[#905] Explicitly get validators from toolkit