UIBarButtonItem removeTitleShadow now also removes the shadow in control state highlighted
UIBarButtonItem removeTitleShadow now also removes the shadow in control
state highlighted

* adds some comments about using NSShadow in the removeTitleShadow
  method
* fixes compiler warnings about implicit type conversions
* fixing some compiler warnings around attributes not being set correctly

ajrulez/FlatUIKit,hanangellove/FlatUIKit,yungfan/FlatUIKit,fromeflow/FlatUIKit,tfrank64/FlatUIKit,applexiaohao/FlatUIKit,yangchenghu/FlatUIKit,GuanKunLuo/FlatUIKit,lydonchandra/FlatUIKit,lioonline/FlatUIKit,AmitaiB/FlatUIKit,somedev/FlatUIKit,zyprosoft/FlatUIKit,hieutn/FlatUIKit,0x73/FlatUIKit,tuanpa199/FlatUIKit,algoaccess/FlatUIKit,nathankot/FlatUIKit,hessu/FlatUIKit,ChaosCoder/FlatUIKit,brextonpham/FlatUIKit,SummerHanada/FlatUIKit,Grouper/FlatUIKit,imjerrybao/FlatUIKit