- Linting (ESLint): Stricter rules (or switch to warning)

- Breaking internal API change: `updateGripCursor` moved to be class method of Selector rather than instance method
- Breaking internal API change: `subpathIsClosed` moved to be class method of `Path` rather than instance method
- Refactoring: Reuse utilities base64 encoder for SVG icons plugin
- Docs (JSDoc): Fix return of the `mouseUp` (can also be an object) and `mouseDown` (may also be a boolean) of `pathActions`; other JSDoc additions/improvements

test/qunit/qunit-assert-almostEquals.js

@@ -1,5 +1,12 @@
 const NEAR_ZERO = 5e-6; // 0.000005, Firefox fails at higher levels of precision.
 
+/**
+ * Checks that the supplied values are equal with a high though not absolute degree of precision.
+ * @param {Float} actual
+ * @param {Float} expected
+ * @param {string} message
+ * @returns {undefined}
+ */
 function almostEquals (actual, expected, message) {
   message = message || (actual + ' did not equal ' + expected);
   this.pushResult({
@@ -10,6 +17,10 @@ function almostEquals (actual, expected, message) {
   });
 }
 
+/**
+ * @param {external:qunit} QUnit
+ * @returns {external:qunit} The same instance passed in after extending
+ */
 export default function extend (QUnit) {
   QUnit.extend(QUnit.assert, {
     almostEquals