Support new ProjectionStyle trait

Author: gaurav-arya

src/fft.jl

@@ -984,3 +984,7 @@ function *(p::r2rFFTWPlan{T,K,true}, x::StridedArray{T}) where {T,K}
     unsafe_execute!(p, x, x)
     return x
 end
+
+AbstractFFTs.ProjectionStyle(::cFFTWPlan) = AbstractFFTs.NoProjectionStyle()
+AbstractFFTs.ProjectionStyle(::rFFTWPlan{T, FORWARD}) where {T} = AbstractFFTs.RealProjectionStyle()
+AbstractFFTs.ProjectionStyle(p::rFFTWPlan{T, BACKWARD}) where {T} = AbstractFFTs.RealInverseProjectionStyle(p.osz[first(p.region)])