Fix dotvisualizer import error

firrtl-diagrammer library was removed from load-ivy.sc due to json4s
compatibility issues with Chisel 3.6. Thus, we shall remove obsolete
dotvisualizer import from cell-5.

Alternative visualization functions (visualize, visualizeHierarchy) are
implemented directly in source/load-ivy.sc and work without this import.

Closes #12

Author: jserv

2.1_first_module.ipynb

@@ -51,13 +51,7 @@
    "execution_count": null,
    "metadata": {},
    "outputs": [],
-   "source": [
-    "import chisel3._\n",
-    "import chisel3.util._\n",
-    "import chisel3.tester._\n",
-    "import chisel3.tester.RawTester.test\n",
-    "import dotvisualizer._"
-   ]
+   "source": "import chisel3._\nimport chisel3.util._\nimport chisel3.tester._\nimport chisel3.tester.RawTester.test"
   },
   {
    "cell_type": "markdown",
@@ -382,4 +376,4 @@
  },
  "nbformat": 4,
  "nbformat_minor": 2
-}
+}