Document _design_docs handler
Document _design_docs handler

COUCHDB-1145

andywenk/couchdb-documentation,KimStebel/couchdb-documentation,andywenk/couchdb-documentation,kxepal/couchdb-documentation,robertkowalski/couchdb-documentation,robertkowalski/couchdb-documentation,micah/couchdb-documentation,robertkowalski/couchdb-documentation,KimStebel/couchdb-documentation,cloudant/couchdb-documentation,kxepal/couchdb-documentation,micah/couchdb-documentation,kxepal/couchdb-documentation,andywenk/couchdb-documentation,KimStebel/couchdb-documentation,micah/couchdb-documentation,robertkowalski/couch-doc-test,robertkowalski/couch-doc-test,robertkowalski/couch-doc-test,cloudant/couchdb-documentation