Change getObjects method to filter by objType or name or by both

The previous condition for the if loop ONLY worked if both the objType
and name were BOTH present.  If a user wanted to filter by just the
objType or just the name, it was not possible.  I've rewritten the code
to allow this feature.

ldurniat/berry.lua

@@ -904,9 +904,18 @@ function M.new( filename, tilesetsDirectory )
 
 				object = layer[j]
 
-				if ( not name or object.name == name ) and ( not objType or object.type == objType ) then
+				if name and objType then -- must match both
+					if ( object.name == name ) and ( object.type == objType ) then
+
+						objects[#objects + 1] = object
+
+					end
+				else  -- must match one
+					if ( object.name == name ) or ( object.type == objType ) then
+
+						objects[#objects + 1] = object
 
-					objects[#objects + 1] = object
+					end
 
 				end