Handle quoting natively.

This is so "settext,'Foo &START; bar';x,10" will be parsed as two commands,
not three.  This hasn't been needed so far, since places that load actor
commands have been calling ReplaceMarkers first, so the entity is replaced
before this; that's going away, so handle it here.

stepmania/src/Command.cpp

@@ -70,11 +70,55 @@ CString Command::GetOriginalCommandString() const
 	return join( ",", m_vsArgs );
 }
 
+static void SplitWithQuotes( const CString sSource, const char Delimitor, vector<CString> &asOut, const bool bIgnoreEmpty )
+{
+	/* Short-circuit if the source is empty; we want to return an empty vector if
+	 * the string is empty, even if bIgnoreEmpty is true. */
+	if( sSource.empty() )
+		return;
+
+	size_t startpos = 0;
+	do {
+		size_t pos = startpos;
+		while( pos < sSource.size() )
+		{
+			if( sSource[pos] == Delimitor )
+				break;
+
+			if( sSource[pos] == '"' || sSource[pos] == '\'' )
+			{
+				/* We've found a quote.  Search for the close. */
+				pos = sSource.find( sSource[pos], pos+1 );
+				if( pos == string::npos )
+					pos = sSource.size();
+				else
+					++pos;
+			}
+			else
+				++pos;
+		}
+
+		if( pos-startpos > 0 || !bIgnoreEmpty )
+		{
+			/* Optimization: if we're copying the whole string, avoid substr; this
+			 * allows this copy to be refcounted, which is much faster. */
+			if( startpos == 0 && pos-startpos == sSource.size() )
+				asOut.push_back( sSource );
+			else
+			{
+				const CString AddCString = sSource.substr( startpos, pos-startpos );
+				asOut.push_back( AddCString );
+			}
+		}
+
+		startpos = pos+1;
+	} while( startpos <= sSource.size() );
+}
+
 void ParseCommands( const CString &sCommands, Commands &vCommandsOut )
 {
 	CStringArray vsCommands;
-	split( sCommands, ";", vsCommands, true );	// do ignore empty
-	
+	SplitWithQuotes( sCommands, ';', vsCommands, true );	// do ignore empty
 	vCommandsOut.v.resize( vsCommands.size() );
 
 	for( unsigned i=0; i<vsCommands.size(); i++ )