fix: Support scrolling in dEDITMULTI (#431)

Also implement missing POKE$ in compiler, various other dialog UI
issues.

fixes #416

Author: tomsci

examples/Tests/dialog.opo

@@ -155,11 +155,17 @@ PROC cancelDlg:
 ENDP
 
 PROC editMultiDlg:
-	LOCAL result%, buf&(16), ptr&, text$(60), len&
+	LOCAL result%, buf&(16), ptr&, text$(60), len&, i%
+	i% = 0
+	WHILE i% < 20
+		text$ = text$ + NUM$(i%, 2) + CHR$(7)
+		i% = i% + 1
+	ENDWH
+
 	ptr& = ADDR(buf&())
-	buf&(1) = 8
-	buf&(2) = &64636261
-	buf&(3) = &67666507
+	POKE$ ptr& + 3, text$
+	POKEL ptr&, LEN(text$)
+
 	dINIT "Multi edit"
 	dEDITMULTI ptr&, "Prompt", 20, 5, 60
 	dTEXT "Another", "Option", KDTextAllowSelection%

examples/Tests/dialog.txt

@@ -34,7 +34,7 @@ PROC bigmenu%:
 	mCASC "Create new", "File...", %n, "Folder...", %N
 	mCASC "Close", "File", %e, "Folder", %z, "All files", %E
 	mCASC "List", "List open files...", %j, "List recent files...", %J
-	mCARD "File", "Open", %o, "Create new>", 16, "Close>", -17, "Delete...", %d, "Rename...", %r, "Properties...", -%p, "List>", 18, "Browse folders...", %g
+	mCARD "File", "Open", %o, "Create new>", 16, "Close>", -17, "Delete...", %d, "Rename...", %r, "Properties...", -%p, "List>", 18, "Browse folders...", %g, "Doom", %d
 
 	mCASC "Find files", "Find files...", %f, "Find again...", %F
 	mCARD "Edit", "Cut (move)", %x, "Copy", %c, "Paste", %v, "Clear clipboard", %X, "Select all", -%a, "Set bookmark", %B, "Go to bookmark", -%b, "Find files>", 19

examples/Tests/menu.opo

@@ -567,6 +567,7 @@ Callables = {
     POKEB = Op("PokeB", {SiboInt, Int}),
     POKEF = Op("PokeD", {SiboInt, Float}),
     POKEL = Op("PokeL", {SiboInt, Long}),
+    ["POKE$"] = Op("PokeStr", {SiboInt, String}),
     POKEW = Op("PokeW", {SiboInt, Int}),
     POS = Fn("Pos", {}, Int),
     POSITION = Op("Position", {Int}),