Removed Depracated M_PI warnings

[Awalz]

I have removed all M_PI warnings and replaced with the appropriate Swift 3.1 version.

[rogomantik]

Hi @Awalz ,
I did this way
for example replacing
endAngle: CGFloat((2 * M_PI) - M_PI),
with
endAngle: (2 * CGFloat.pi) - CGFloat.pi,
instead of
CGFloat((2 * Double.pi) - Double.pi),
it is the same or is better to use double and then cast to float?