fix(classes): cleanup resources, add cancellable timeouts, and fix bugs in several core utility classes

ts/classes.interestmap.ts

@@ -70,6 +70,8 @@ export class InterestMap<DTInterestId, DTInterestFullfillment> {
     if (!returnInterest) {
       returnInterest = newInterest;
       this.interestObjectMap.add(returnInterest);
+    } else {
+      newInterest.destroy(); // clean up abandoned Interest's timers
     }
     this.interestObservable.push(returnInterest);
     return returnInterest;
@@ -131,4 +133,16 @@ export class InterestMap<DTInterestId, DTInterestFullfillment> {
     });
     return interest; // if an interest is found, the interest is returned, otherwise interest is null
   }
+
+  /**
+   * destroys the InterestMap and cleans up all resources
+   */
+  public destroy() {
+    const interests = this.interestObjectMap.getArray();
+    for (const interest of interests) {
+      interest.destroy();
+    }
+    this.interestObjectMap.wipe();
+    this.interestObservable.signalComplete();
+  }
 }