loadConfig should accept array of config, not just file path

[matmar10]

Currently, loadConfig only accepts a file path. However, an equally reasonable approach is to pass the array of plugin definitions directly to loadConfig.

loadConfig supports a JS file, but it requires synchronous loading and return of the plugin list directly via module.exports, which may not be feasible in all applications.

Proposed change adds the following capability:

loadConfig(configArray, base, [callback])

• configArray array of plugins to load with their configuration
• base location to use as the base for plugins
• callback an (optional) callback

PR inbound.