couch_db tools to print old versions statistics and body

Currently couch_dbinfo does NOT print anything about old versions of documents.

Currently couch_dbdump has now way of dumping old versions of documents.

[vend1@cust1sdf2db11 ~]$ sudo /opt/couchbase/bin/couch_dbinfo /tmp/996.couch.nok

[sudo] password for vend1: 

DB Info (/tmp/996.couch.nok) - header at 6696960

   file format version: 11

   update_seq: 19801193

   doc count: 1096

   deleted doc count: 20787

   data size: 2.90 MB

   B-tree size: 1.95 MB

   total disk size: 6.39 MB

[vend1@cust1sdf2db11 ~]$ 

couch_dbinfo does give "deleted doc count" and
couch_dbdump does contain "deleted entries".

BUT

they don't contain previous versions of same document.

couchdb file format is said to be append-only.

for analysis of different problems we need to look into old versions of documents.

please consider to add a line to couch_dbinfo output, like this:

    old doc count: 10960

    old data size: 3.2 MB

please consider to add a command lile key to couch_dbdump, like this:

  --old-docs

to allow output of documents, that were later overwritten with new versions.