couch-doc-diff: diff of a document on the couch (feature 3485)

Added the bash script couch-doc-diff.
It runs a diff between the content of the couch document specified as the first parameter and the second parameter.
Diff returns 0 if there is no difference. This way you can tell the data is already on the couch.
The diff will ignore changes to whitespaces as these are usually irrelevant for security json docs.
couch:document - ensure state of a couch document - (feature #3485)

also made the use of host, hostname and port a bit more consistent.
use couchdb::document to create bigcouch node config (feature #3485)

fixes the use of couch-doc-update with non standart hosts
replaces couchdb::bigcouch::query with couchdb::bigcouch::document
minor: cleanup spacing (feature #3485)