Dispose not removing timers and exception handlers

[bragma]

As per subject, the public "dispose()" method in the main ApplicationInsights class calls "dispose()" on each internal static instances of console, exceptions, performance and requests. But in the implementation of those methods, not all resources are released. As an example:

https://github.com/Microsoft/ApplicationInsights-node.js/blob/master/AutoCollection/Exceptions.ts

class AutoCollectExceptions {
...
    public enable(isEnabled: boolean) {
        if(isEnabled) {
...
                process.on("uncaughtException", this._exceptionListenerHandle);
            }
        } else {
...
                process.removeListener("uncaughtException", this._exceptionListenerHandle);
...
            }
        }
    }

    public dispose() {
        AutoCollectExceptions.INSTANCE = null;
        // <<<<---- What about calling "this.enable(false)" here?
        this._isInitialized = false;
    }

Same goes for performance.

In my tests I use the "dispose()" method to reset AI's SDK to a pristine state. This is required because AI creates a global singleton and even reloading it with another require(), the same instance is returned due to node's module caching.
After some tests, node complains about an handler leek because handlers are added on each test.

My suggestion is to call "enable(false)" in the dispose call if you agree. I can make a PR for this if you like.