ibeacon.d.ts startAdvertising parameter measuredPower should be optional

[petemcwilliams]

I'm submitting a ... (check one with "x")
[ x ] bug report
[ ] feature request

Current behavior:
Calling startAdvertising requires the measuredPower parameter to be set.

Expected behavior:
measuredPower should be an optional parameter to startAdvertising to match description and CLLocationManager code for cordova plugin petermetz/cordova-plugin-ibeacon

     * @param {Integer} measuredPower: Optional parameter, if left empty, the device will
     * use it's own default value.

CDVLocationManager.m =

            BOOL measuredPowerSpecifiedByUser = command.arguments.count > 1;
            NSNumber *measuredPower = nil;
            if (measuredPowerSpecifiedByUser) {
                measuredPower = [command.arguments objectAtIndex: 1];
                [[self getLogger] debugLog:@"Custom measuredPower specified by caller: %@", measuredPower];
            } else {
                [[self getLogger] debugLog:@"[Default measuredPower will be used."];
            }

Steps to reproduce:
IBeacon.startAdvertising(region) // ts: Supplied parameters do not match any signature of call target.

Other information:

package.json info:

    "dependencies": {
        "@angular/common": "2.4.8",
        "@angular/compiler": "2.4.8",
        "@angular/compiler-cli": "2.4.8",
        "@angular/core": "2.4.8",
        "@angular/forms": "2.4.8",
        "@angular/http": "2.4.8",
        "@angular/platform-browser": "2.4.8",
        "@angular/platform-browser-dynamic": "2.4.8",
        "@angular/platform-server": "2.4.8",
        "@ionic/storage": "1.1.7",
        "ionic-angular": "2.2.0",
        "ionic-native": "^2.9.0",
        "ionicons": "3.0.0",
        "rxjs": "5.0.1",
        "sw-toolbox": "3.4.0",
        "zone.js": "0.7.2"
    },
    "devDependencies": {
        "@ionic/app-scripts": "1.1.4",
        "@types/core-js": "^0.9.35",
        "typescript": "2.0.9"
    },