[bp] MB-8286 Friendly error if emitted value is too big

Instead of ending up in badmatch error during reduce when
a map emitted value is too big, report an explicit, and much
more user friendly, error message telling the value is too
big and the corresponding document ID, key and byte size.

E.g. of the previous badmatch:

couchdb:error,2013-04-12T18:57:47.396,ns_1@8.29.113.41:<0.17680.6>:couch_log:error:42]Uncaught error in HTTP request: {throw,
                                 {error,
                                  {function_clause,
                                   [{couch_set_view_util,parse_values,
                                     [<<"gNd+/UCzPu5Anj80gGZ/Q8AUf/V/a8B6Ps8BLv6Sga/+WQI8fhNCnX4bgsV+PoLz/dkDKH3GA1L9zkOxvaXD872nRA5
B2D56AlL+PsKffikCq35hgrY+tIKj/x+Cj//wgkjAkUJ1gORCN8DZAekAvgG0f+QB1H86AdU+U0HyfeDBvP2pwXU9tcDifj4Abj6CwHJ/I0A8/63/1ECnf+CBdUAJAd8AoMH [<<"yAFY+Bj+6vsV+83+BPlKACj4XQCe94gAY/cFANL32/7J+BH+U/qD/dX8CPwQAAb6+wIu+fAEcfkIBjn6zgYn+1kHAf <<"gKZ+N0Cd/kVAxX7ywJi/bsBYP8tARYBXAAfA6z+zgWO/JEJ2vgmDuvzWhOA7jkYculQG4nmBRzf5gQbBukEGXHrcRa <<"7P9RQKA/tMAgf8w/y4A3f1OAD79UAD9/FEAAP0RAHz9wv8c/nb/x/45/1D/dv9b/yMAa//pAJD/igFC/4oBqf46AbH <<"{\"BINARYDATA\":\"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA {couch_set_view_util,expand_dups,2}, {couch_set_view_group, '-init_group/3-fun-3-',7}, {couch_btree,'-write_node/3-lc$^0/1-0-',5}, {couch_btree,write_node,3}, {couch_btree,modify_node,8}, {couch_btree,modify_kpnode,10}, {couch_btree,modify_node,8}]}}}Stacktrace: [{couch_set_view,get_group,3}, {couch_set_view,get_map_view,4}, {couch_view_merger,get_set_view,5}, {couch_view_merger,simple_set_view_query,3}, {couch_httpd,handle_request,6}, {mochiweb_http,headers,5}, {proc_lib,init_p_do_apply,3}]

Change-Id: If573cf4ae029a6c4413c1df37de3db3b51ba3e61
Reviewed-on: http://review.couchbase.org/27072
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Filipe David Borba Manana <fdmanana@gmail.com>
Reviewed-on: http://review.couchbase.org/30155