Integrate new reference line

Planning: (1) adjusted kappa and dkappa bounds; (2) fixed reference line length to 100m or 250m to avoid SQP re-init.

planning: dynamically adjust reference line length based on ADC speed. reduce path calculation cost in local scenario. (#729)

Planning: use 0.01s for output trajectory. restored planning_cycle_time as no failure is observed now at turnning.

Planning: used gflag to disable using planning_cycle_time in trajectory stitcher. extended planning time to 8s, distance to 250m to avoid failure at turning.

Planning: set minimum spline number to 1, and added check before adding third derivative constraints in qp path optimizer. (#630)

fails. fixed init point printout bug.

Planning: Fixed bugs for high speed cruising; updated unit tests; added a TODO for a potential pointer crash in math.