Fixed the inability to add rows by using a BindingList instead of an IEnumerable.

Signed-off-by: Melissa Avery-Weir <melissa.avery@wellsfargo.com>

d20 SRD Spell Lists/Models/SpellSet.cs

@@ -45,7 +45,7 @@ namespace d20_SRD_Spell_Lists.Models {
             userSpellList.Add(xElement);
         }
 
-        public IEnumerable<Spell> byClass(Character.SpellCastingClasses spellCastingClass) {
+        public IList<Spell> byClass(Character.SpellCastingClasses spellCastingClass) {
             List<Spell> spells = new List<Spell>();
 
             filterMasterSpellsByClass(spellCastingClass, spells);