Create dialog for editing large terrain object definitions

- Remove keybindings from terrain dialog arrow buttons
- Fix arrow buttons not bound-checking fields

Dialog engine:
- Fix fields crashing after text is set while it has focus
- Trigger focus handler on untoast() to balance that in toast()

src/dialogxml/dialog.cpp

@@ -1246,6 +1246,8 @@ bool cDialog::toast(bool triggerFocus){
 
 void cDialog::untoast() {
 	dialogNotToast = true;
+	if(!currentFocus.empty())
+		this->getControl(currentFocus).triggerFocusHandler(*this, currentFocus, false);
 }
 
 bool cDialog::accepted() {

src/dialogxml/field.cpp

@@ -59,6 +59,14 @@ bool cTextField::triggerFocusHandler(cDialog& me, std::string id, bool losingFoc
 	return passed;
 }
 
+void cTextField::setText(std::string to) {
+	cControl::setText(to);
+	if(haveFocus)
+		insertionPoint = to.length();
+	else insertionPoint = -1;
+	selectionPoint = 0;
+}
+
 void cTextField::set_ip(location clickLoc, int cTextField::* insertionPoint) {
 	TextStyle style;
 	style.font = FONT_PLAIN;
@@ -480,7 +488,11 @@ void cTextField::handleInput(cKey key) {
 		case key_insert:
 			break;
 	}
+	// Setting the text normally resets insertion/selection point, but we don't want that here.
+	int ip = insertionPoint, sp = selectionPoint;
 	setText(contents);
+	insertionPoint = ip;
+	selectionPoint = sp;
 }
 
 cControl::storage_t cTextField::store() {

src/dialogxml/field.hpp

@@ -41,6 +41,7 @@ public:
 	void setFormat(eFormat prop, short val) throw(xUnsupportedProp);
 	short getFormat(eFormat prop) throw(xUnsupportedProp);
 	void setColour(sf::Color clr) throw(xUnsupportedProp);
+	void setText(std::string to);
 	storage_t store();
 	void restore(storage_t to);
 	/// Get the current input type of the field.