Updated NACA4 return format and added normals func

Changed the format that the NACA4 file returns the calculated airfoil
in.

added calc_normal_vectors function

added the "End of File" comment to a bunch of files
added colocation, renamed line_x_constant files, mod NACA

added a function that finds the colocation points, of the airfoil

renamed the line_x_constant_2d to not have a _2d

added an extra return value, trailing_edge, to NACA4