updated the ATL07 notebook and added a demo file, which should be ignored

Author: akpetty

seaice/ATL07-01_20181115003141_07240101_001_01_BRW.default.default1.jpg

@@ -1846,7 +1846,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python [default]",
    "language": "python",
    "name": "python3"
   },
@@ -1860,7 +1860,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.7"
+   "version": "3.6.5"
   }
  },
  "nbformat": 4,