remove mixed integer path planning

Author: AtsushiSakai

PathPlanning/MixIntegerPathPlanning/animation.gif

@@ -46,7 +46,6 @@ Python codes for robotics algorithm.
       * [Dubins path planning](#dubins-path-planning)
       * [Reeds Shepp planning](#reeds-shepp-planning)
       * [Optimal Trajectory in a Frenet Frame](#optimal-trajectory-in-a-frenet-frame)
-      * [Mix Integer Optimization based model predictive planning and control](#mix-integer-optimization-based-model-predictive-planning-and-control)
    * [Path tracking](#path-tracking)
       * [Pure pursuit tracking](#pure-pursuit-tracking)
       * [Stanley control](#stanley-control)
@@ -438,26 +437,6 @@ Ref:
 - [Optimal trajectory generation for dynamic street scenarios in a Frenet Frame](https://www.youtube.com/watch?v=Cj6tAQe7UCY)
 
 
-
-## Mix Integer Optimization based model predictive planning and control
-
-![2](https://github.com/AtsushiSakai/PythonRobotics/blob/master/PathPlanning/MixIntegerPathPlanning/animation.gif)
-
-A model predictive planning and control code with mixed integer programming.
-
-It is based on this paper.
-
-- [MIXED INTEGER PROGRAMMING FOR MULTI-VEHICLE PATH PLANNING](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.4.2591&rep=rep1&type=pdf)
-
-This code uses cvxpy as an optimization modeling tool,
-
-- [Welcome to CVXPY 1\.0 — CVXPY 1\.0\.0 documentation](https://cvxgrp.github.io/cvxpy/index.html)
-
-Gurobi is used as a solver for mix integer optimization problem.
-
-- [Gurobi Optimization \- The State\-of\-the\-Art Mathematical Programming Solver](http://www.gurobi.com/)
- 
-
 # Path tracking
 
 ## Pure pursuit tracking