Refactor syntax unicode find

Updates on:

MCStack::markfind(MCExecPoint&, Find_mode, MCString const&, MCChunk*, Boolean)
MCStack::breakstring(MCString const&, MCString**, unsigned short&, Find_mode)
MCStack::findone(MCExecPoint&, Find_mode, MCString const*, unsigned short, MCChunk*, Boolean)
MCStack::find(MCExecPoint&, Find_mode, MCString const&, MCChunk*)
MCField::find(MCExecPoint&, unsigned int, Find_mode, MCString const&, Boolean)
MCCard::find(MCExecPoint&, Find_mode, MCString const&, Boolean, Boolean)