Add example Variant values with larger numbers of fields / array elements

[alamb]

• Add example binary variant data and regeneration scripts #76 adds example variant binary values

Variant is a binary format similar to JSON but allows more types in its value fields.

There are basic tests for nested structures object and list that have a few elements such as:

[ 1, 2, 3, 4]

And

{ 
 "field1": 1
}

The examples added so far have few enough fields to be encoded with an 8 byte offset. However, the Variant spec includes variable sized offsets for objects with a larger number of fields or elements

[ 1, 2, 3, 4, ...  4000000 ]

And

{ 
 "field1": 1
...
"field400000": 123
}

Here are the type of objects that do not have examples:

• object with 300 fields (more than 2^8 = 256) fields (requires a more than 1 byte num_elements)
• object with 66,000 fields (more than 2^16 = 65,536 fields) requires a 3 byte field id / offset
• object with 17M fields (more than 2^25 = 16,777,216 fields) requires a 4 byte field id / offset

This ticket tracks adding example Variant vales for such values. I did not add it to the original PR as I worried the binary items would be too large