Able to Start Multiple Instances of SwiftMetrics Leading to Display Issues

[jonathan-spruce]

As SwiftMetrics is now already included when using kitura init, adding the following code starts a second SwiftMetrics instance leading to the dashboard displaying multiple versions of each metric (e.g. memory, cpu, etc.) and display issues with the tables:

import SwiftMetrics
import SwiftMetricsDash

// Enable SwiftMetrics Monitoring
let sm = try SwiftMetrics()

// Pass SwiftMetrics to the dashboard for visualising
let smd = try SwiftMetricsDash(swiftMetricsInstance : sm)

Screenshot of issue:

Environment Details

macOS 10.13.5, Swift 4.2.1, Xcode 9.4.1

Steps to Reproduce

1. Run kitura init to create a new project
2. Add the above code to the project
3. Run the project and access the SwiftMetricsDash from localhost:[port_no]/swiftmetrics-dash
4. Each metrics graph is duplicated multiple times and incorrectly displayed.