distinguish vertical case and horizontal case

When orientation setting to vertical and horizontal.
The position of joint in path is different.

The joint should be at one x/y spacing later to its parent node,
and at same y/x to child node.
Example, if the orientation is vertical, and we have to insert a
joint. The joint's x is same x to new commit, and y is a spacing
back to its parent.

Author: yodalee

src/gitgraph.js

@@ -770,11 +770,19 @@
       this.pushPath(this.startPoint);
       // Add a path joint to startpoint + template spacing
       // So that line will not go through commit of other branches
-      this.pushPath({
-        x: commit.x,
-        y: this.startPoint.y - this.template.commit.spacingY,
-        type: "joint"
-      });
+      if ((this.parent.orientation === "vertical-reverse") || (this.parent.orientation === "vertical")) {
+        this.pushPath({
+          x: commit.x,
+          y: this.startPoint.y - this.template.commit.spacingY,
+          type: "joint"
+        });
+      } else {
+        this.pushPath({
+          x: this.startPoint.x - this.template.commit.spacingX,
+          y: commit.y,
+          type: "joint"
+        });
+      }
     } else if (isPathBeginning) {
       point.type = "start";
     }