Make size work for primitives

[justinbmeyer]

What should size return for:

• undefined
• NaN
• 5
• false
• "abc"
• {} -> empty object

@bmomberger-bitovi 's suggestions:

• undefined - 0
• NaN - 0
• 5 - 1
• false - 1
• "abc" - 3
• {} - 0