Update README and perform some cleanup

.github/workflows/checkin.yml

@@ -1,25 +0,0 @@
-name: "PR Checks"
-on: [pull_request, push]
-
-jobs:
-  check_pr:
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v1
-
-    - name: "npm ci"
-      run: npm ci
-
-    - name: "npm run build"
-      run: npm run build
-
-    - name: "npm run test"
-      run: npm run test
-
-    - name: "check for uncommitted changes"
-      # Ensure no changes, but ignore node_modules dir since dev/fresh ci deps installed.
-      run: |
-        git diff --exit-code --stat -- . ':!node_modules' \
-        || (echo "##[error] found changed files after build. please 'npm run build && npm run format'" \
-                 "and check in all changes" \
-            && exit 1)