add g64 doc

documentation/Blendercam-Panel-Descriptions.md

@@ -175,6 +175,7 @@ If not enabled then the Material origin and Material size are used in case when
 ## CAM movement panel
 ![CAM Movement](images/camMovement.png)
 
+* **G64 trajectory** This enables the "naive cam detector" and enables blending with a tolerance. If you program G64 P0.05, you tell the planner that you want continuous feed, but at programmed corners you want it to slow down enough so that the tool path can stay within 0.05 user units of the programmed path. The exact amount of slowdown depends on the geometry of the programmed corner and the machine constraints, but the only thing the programmer needs to worry about is the tolerance. This gives the programmer complete control over the path following compromise. 
 * **Movement type** - is supported only for some of the strategies, sets up how the cutter moves into the material
   * **Meander/ZigZag** - sometimes also called ZigZag , this means you don't care which direction the cutter goes into the material.
   * **Climb/Down Milling** - the default movement, and mostly used when doing CNC machining if the machine has no or very little backlash. The cutter rotates with the direction of the feed. It can produce a better finish, less stress on the bit, and less power required. If the machine has backlash then Conventional milling is a better choice.