`List` data type

[BjornDCode]

Stencil currently doesn't have a List or Array data type.

Developers should be able to defined lists with the following syntax:

['one', 'two', 'three',]

• A list should be able to contain any Stencil data type
• A list should be able to contain different data types at the same time
• Items should be separated by ','
• A trailing ',' is optional after the last item