This commit:
* Reorders the Netplay settings menu to put more useful options at the
top.
* Renames the swap_input setting from "Swap Netplay Input", which is
meaningless and confusing, to "Netplay P2 Uses C1", which is oddly
truncated but at least true.
* Removes the is_client setting altogether, as that's no longer how
client vs. server mode is determined (each are separate options when
enabling Netplay)
