Cross realm fix

I removed all calls to GetUnitName("player") and made the variables
playerName and playerFullName instead.
I chose to Ambiguate() everywhere playerName gets displayed as the
addon's frames just isn't big enough.
Loot History is only handed playerName to preserve old records, and as
realmName isn't really needed.
This assumes Blizzard provides playerName-realmName on all calls listed
below, but I doubt they do if a player is from the same server
as the caller - most places it can be fixed with Ambiguate(unit, "none")
- however.

Untested functions:
GetMasterLootCandidate()
GetRaidRosterInfo()
GetGuildRosterInfo()

Also, if they return playerName-realmName we need to find out if
realmName includes spaces.
UnitFullName("player") in GetFullPlayerName() returns realmName without
spaces - with spaces is returned from GetRealmName()