Extend a projection to all of the integers -n/2+1 -> n/2
extproj = ExtendProj(projj,n,windows,sympts,sym)
windowed projection vector
length of full signal
string selecting windows used in windowing projection 'm' -> mother, 'f' -> father, 't' -> truncated mother
points of symmetry and antisymmetry of projection
string: symmetry type; 'e' -> even ;'o' -> odd