Hard-Coded sizes

[avrahamshukron]

in addPullToRefreshHeader method, all the sizes are hard-coded which is really bad.

For example,
refreshHeaderView = [[UIView alloc] initWithFrame:CGRectMake(0, 0 - REFRESH_HEADER_HEIGHT, 320, REFRESH_HEADER_HEIGHT)];

Should be:
CGSize tableViewSize = self.tableView.frame.size;
refreshHeaderView = [[UIView alloc] initWithFrame:CGRectMake(0, 0 - REFRESH_HEADER_HEIGHT, tableViewSize.width, REFRESH_HEADER_HEIGHT)];