handle url cells as values of buildDocURL, couchGet and couchReq
handle url cells as values of buildDocURL, couchGet and couchReq

When passing url cell instead of url we'll do the right thing by
either returning another url cell (buildDocURL) or by running query
after getting defined value from cell (couchReq and couchGet).

Change-Id: I84cdbecb9e12c69dd2ea43f05cedcf659ed4bde4
Reviewed-on: http://review.couchbase.org/10414
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

membase/ns_server,nimishzynga/ns_server,daverigby/ns_server,ceejatec/ns_server,daverigby/ns_server,ceejatec/ns_server,mschoch/ns_server,membase/ns_server,nimishzynga/ns_server,daverigby/ns_server,mschoch/ns_server,pavel-blagodov/ns_server,nimishzynga/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,mschoch/ns_server,vzasade/ns_server,membase/ns_server,ceejatec/ns_server,membase/ns_server,vzasade/ns_server,t3rm1n4l/ns_server,pavel-blagodov/ns_server,pavel-blagodov/ns_server,vzasade/ns_server,nimishzynga/ns_server,vzasade/ns_server,mschoch/ns_server,mschoch/ns_server,nimishzynga/ns_server,membase/ns_server,ceejatec/ns_server,mschoch/ns_server,daverigby/ns_server,ceejatec/ns_server,nimishzynga/ns_server,t3rm1n4l/ns_server,membase/ns_server,t3rm1n4l/ns_server,daverigby/ns_server,t3rm1n4l/ns_server,pavel-blagodov/ns_server