added placementModes and mesh testing

can place varying values into grid, starting to work on rendering meshes to represent the cells

Pathfinding Visualizer/Assets/Scripts/MeshTesting.cs

@@ -0,0 +1,39 @@
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+public class MeshTesting : MonoBehaviour
+{
+    void Start()
+    {
+
+        Debug.Log("Mesh Testing");
+
+        Mesh mesh = new Mesh();
+
+
+        // Build required data-structures for triangle mesh
+        Vector3[] vertices = new Vector3[3];
+        Vector2[] uv = new Vector2[3];
+        int[] triangles = new int[3];
+
+        // Set vertices of polygon (triangle)
+        vertices[0] = new Vector3(  0,   0);
+        vertices[1] = new Vector3(  0, 100);
+        vertices[2] = new Vector3(100, 100);
+
+        // Set order of indexes of vertices to draw polygon (v1 -> v2 -> v3 -> v1)
+        // Note: always set clockwise, otherwise mesh will be facing backwards
+        triangles[0] = 0;
+        triangles[1] = 1;
+        triangles[2] = 2;
+
+
+        mesh.vertices = vertices;
+        mesh.uv = uv;
+        mesh.triangles = triangles;
+
+        GetComponent<MeshFilter>().mesh = mesh;
+        
+    }
+}