town details cancel button (#685)

rsrc/dialogs/edit-town-details.xml

@@ -1,7 +1,7 @@
 <?xml version='1.0' encoding='UTF-8' standalone='no'?>
 <!-- NOTE: This file should be updated to use relative positioning the next time it changes. -->
 <?xml-stylesheet href="dialog.xsl" type="text/xsl"?>
-<dialog defbtn='okay'>
+<dialog defbtn='okay' escbtn='cancel'>
 	<pict type='dlog' num='16' top='8' left='8'/>
 	<text size='large' top='6' left='50' width='256' height='17'>Town Details</text>
 
@@ -50,6 +50,6 @@
 		<field name='comment' top='317' left='162' width='251' height='80'/>
 	</stack>
 
-	<!-- OK button -->
 	<button name='okay' type='regular' top='410' left='349'>OK</button>
+	<button name='cancel' type='regular' relative='neg pos-in' rel-anchor='prev' top='0' left='71'>Cancel</button>
 </dialog>

src/scenedit/scen.townout.cpp

@@ -713,6 +713,7 @@ void edit_town_details() {
 	using namespace std::placeholders;
 	cDialog town_dlg(*ResMgr::dialogs.get("edit-town-details"));
 	town_dlg["okay"].attachClickHandler(save_town_details);
+	town_dlg["cancel"].attachClickHandler(std::bind(&cDialog::toast, &town_dlg, false));
 	town_dlg["chop"].attachFocusHandler(std::bind(check_range_msg, _1, _2, _3, -1, 10000, "The day the town becomes abandoned", "-1 if it doesn't"));
 	town_dlg["key"].attachFocusHandler(std::bind(check_range_msg, _1, _2, _3, -1, 10, "The event which prevents the town from becoming abandoned", "-1 or 0 for none"));
 	town_dlg["difficulty"].attachFocusHandler(std::bind(check_range_msg, _1, _2, _3, 0, 10, "The town difficulty", "0 - easiest, 10 - hardest"));