Make ID parameter optional.

Add missing class names to table headers.

Use String as the default formatter to prevent errors when rendering non-supported data types (Date, for example).

Update test app.

Add ReadMe for MaterialDataTable.

Feed the field name and data item to the formatter so that it can reference more data to yield a result.

Add basic test cases for MaterialDataTable. Not complete yet.

Remove unneeded code.

Make data optional.

Add getter for root element.

Implement MaterialDataTable.

Make handleExtraHandler support multiple arguments.

Revise test cases.

Add reference and getter of label.

Add element getters.