Improve XModem Startup

- Extended startup timeout for XM.COM so that it doesn't timeout so quickly while host is selecing a file to send.
- Updated SD Card How-To from David Reese.

Doc/ChangeLog.txt

@@ -1,3 +1,7 @@
+Version 3.0.1
+-------------
+- WBW: Increase XModem timeout waiting for host to start sending
+
 Version 3.0.0
 -------------
 - WBW: v2.9.2 -> 3.0 version upgrade due to scope of changes

Source/Apps/XM/xmdm125.asm

@@ -2213,6 +2213,14 @@ ILLDU:	CALL	ERXIT
 ;
 RCVRECD:XRA	A		; Initialize error count to zero
 	STA	ERRCT
+;	
+;WBW BEGIN: Be more patient waiting for host to start sending file
+	LDA	FRSTIM		; WBW: Get first time flag
+	ORA	A		; WBW: Set CPU flags
+	JNZ	RCVRPT		; WBW: If not first time, bypass
+	MVI	A,-10		; WBW: Else increase error limit
+	STA	ERRCT		; WBW: Save error new limit
+;WBW END
 ;
 RCVRPT:	 IF	CONFUN		; Check for function key?
 	CALL	FUNCHK		; Yeah, why not?