Enable stricter typescript checks, remove unused import.

lib/specs.ts

@@ -1,5 +1,5 @@
 import { Point, BBox } from "../vendor/bezier-js";
-import { getBoundingBoxCenter, getBoundingBoxForBeziers } from "./bounding-box";
+import { getBoundingBoxForBeziers } from "./bounding-box";
 import * as colors from "./colors";
 import { pathToShapes } from "./path";
 import type { SvgSymbolElement } from "./vocabulary";
@@ -19,7 +19,6 @@ export type Specs = {
   crown?: PointWithNormal[];
   nesting?: BBox[];
 };
-
 const NUM_ARROW_POINTS = 4;
 const ARROW_TOP_POINT_IDX = 0;
 const ARROW_BOTTOM_POINT_IDX = 2;

tsconfig.json

@@ -35,10 +35,10 @@
     // "alwaysStrict": true,                  /* Parse in strict mode and emit "use strict" for each source file. */
 
     /* Additional Checks */
-    // "noUnusedLocals": true,                /* Report errors on unused locals. */
+    "noUnusedLocals": true,                /* Report errors on unused locals. */
     // "noUnusedParameters": true,            /* Report errors on unused parameters. */
     // "noImplicitReturns": true,             /* Report error when not all code paths in function return a value. */
-    // "noFallthroughCasesInSwitch": true,    /* Report errors for fallthrough cases in switch statement. */
+    "noFallthroughCasesInSwitch": true,    /* Report errors for fallthrough cases in switch statement. */
     // "noUncheckedIndexedAccess": true,      /* Include 'undefined' in index signature results */
 
     /* Module Resolution Options */