Use FwSizeType instead of U32 for indices
Add operator= with initializer list

Use the single-value constructor when all the element values
are the same

Add initializer list constructor

Use initializer list for array values

Remove multi-element constructor
Use initializer list constructor instead

Pass initializer list by reference in constructor

This seems to help the compiler disambiguate constructor arguments
in some cases

Allow large-size arrays
Add tests

Make single element constructor explicit