Added non-const value_t::begin and value_t::end
Added non-const value_t::begin and value_t::end

jwakely/ledger,afh/ledger,duncanmortimer/ledger,ledger/ledger,duncanmortimer/ledger,ledger/ledger,paulbdavis/ledger,paulbdavis/ledger,jwakely/ledger,jwakely/ledger,duncanmortimer/ledger,duncanmortimer/ledger,afh/ledger,paulbdavis/ledger,ledger/ledger,afh/ledger,jwakely/ledger,jwakely/ledger,jwakely/ledger,ledger/ledger,jwakely/ledger,paulbdavis/ledger,ledger/ledger,afh/ledger,afh/ledger,paulbdavis/ledger,duncanmortimer/ledger,paulbdavis/ledger,duncanmortimer/ledger,paulbdavis/ledger,duncanmortimer/ledger