Make ground truth for instance feature has bugs

[gneworld]

1. code blocks are not aligned?
2. "ground" is defined as np.zeros((len(target_lanes), 1, self.p.grid_yself.p.grid_x, self.p.grid_yself.p.grid_x)), so ground[batch_index][0][i] += gt_one will report IndexError

[koyeongmin]

1. Some parts are never reached. The parts are not necessary. I forgot to remove them after some experiments.
2. temp is reshaped by "temp = temp[temp>-1]" ((1, self.p.grid_y, self.p.grid_x) -> (self.p.grid_y*self.p.grid_x))
   (Sorry, this is not readable. reshape method is more suitable. )
   Also, other indexes are ok.

[gneworld]

@koyeongmin

could you tell me this modification logic is right or not? thanks

[koyeongmin]

Yes, I think that there are no problems.