Additional API methods for the file component

[VizuaaLOG]

Over the next few versions I think it would great to expand the API methods available, allowing certain settings to be changed at run time, rather than needing to recreate the component. The below are ideas for the file component, any other ideas please just comment!

• getFileExtension(): string|array - Returns the file extension for the selected file[s]
• getFileCount(): number - Returns the number of selected files
• hasFileSelected(): boolean - Returns true if at least one file has been selected, false otherwise
• trigger(event_name: string) - This will trigger the provided event on the file instance. Note: This wouldn't be restricted to documented events, so could be used for handling custom events