First pass at custom cursor display

internal/assetstore/assetstore.go

@@ -34,6 +34,9 @@ type AssetStore struct {
 	entries entryMap
 
 	// These members are used to store things we've already loaded
+	cursorObj *Object
+
+	cursors map[CursorName]*Cursor
 	fonts   map[string]*Font
 	generic *data.Generic
 	maps    map[string]*Map
@@ -85,6 +88,8 @@ func (a *AssetStore) Refresh() error {
 	}
 
 	// Refresh
+	a.cursorObj = nil
+	a.cursors = make(map[CursorName]*Cursor)
 	a.entries = newEntryMap
 	a.fonts = make(map[string]*Font)
 	a.maps = make(map[string]*Map)