Improved lane following:
Improved lane following:

* Added helper function to get d coordinate for lanes
* Added high resolution map waypoints for smoother trajectory

BrendanSchell/SDCND_T3_P1,BrendanSchell/SDCND_T3_P1,BrendanSchell/SDCND_T3_P1,BrendanSchell/SDCND_T3_P1,BrendanSchell/SDCND_T3_P1