Describe the bug
It looks like we do not actually need to prescribe unit normal vectors for MARKER_INLET, because it is normalized in the code, e.g. in BC_Inlet. When a 2D inlet is at a 45 degree angle, the normal vector of the inlet can be given as [1.0, 1.0] in the config file. However, when you want to generate and use an inlet profile for this, you will get an error message

ERROR: Found these values in columns 4 - 5
  [1.000000e+00, 1.000000e+00]
  These values should be components of a unit vector for direction,
  but their magnitude is: 1.414214e+00

I suggest to accept non-normalized vectors as input. This simply means that we remove this check for inlet profiles and update the description for the inlet boundary condition: accepts surface normal vector instead of accepts surface unit normal vector