Also renames whitelistalwaysrelay.
Nodes relay all transactions from whitelisted peers, this gets in the way of some useful reasons for whitelisting peers-- for example, bypassing bandwidth limitations.
The purpose of this forced relaying is for specialized gateway applications where a node is being used as a P2P connection filter and multiplexer, but where you don't want it getting in the way of (re-)broadcast.
This change makes it configurable with whitelistforcerelay.