SP2A Update readme

The updated part is

1. Posky Utility Panel  (Just replace)
2. Guages
3.1 Panel/Posky777/PkyNosegearsteerling.xml   <-Updated
3.2 Panel/Posky777/Pky_PB_Towhead.xml  <-New
So copy PkyNosegearsteerling.xml and Pky_PB_Towhead.xml to the Panel/Posky777 folder
Add line to Panel.cfg to make Pky_PB\Towhead.xml work

gauge23=Posky777!Pky_PB_Towhead, 140,80,140,80

