18 add more operations for modifiers (#23)

* Added Operations and Combat Conditions

+ Added Multiply, Division and Subtract operations for modifiers
+ Added Combat Conditions Effects form Ars Armorum

* Added Math.floor()

* Fixed Operations and Combat Conditions

templates/sheets/partial/mod.hbs

@@ -40,6 +40,9 @@
 							<option value="add">{{localize "midgard5.mod-operation-add"}}</option>
 							<option value="set">{{localize "midgard5.mod-operation-set"}}</option>
 							<option value="fixed">{{localize "midgard5.mod-operation-fixed"}}</option>
+							<option value="subtract">{{localize "midgard5.mod-operation-subtract"}}</option>
+							<option value="multiply">{{localize "midgard5.mod-operation-multiply"}}</option>
+							<option value="division">{{localize "midgard5.mod-operation-division"}}</option>
 						{{/select}}
 					</select>
 				</td>