Create Dates with Current Time

[sinclairzx81]

This PR updates the handling of Type.Date when initializing via Value.Create or Value.Cast. Previous to this PR, Dates would initialize to unix epoch (timestamp 0). This PR ensures dates are initialized to the current time.

This behavior is inline with the following.

const date = Value.Create(Type.Date()) // current time

const date = new Date()                // current time

This behavior can be overridden by specifying a default value.

const date = Value.Create(Type.Date({ default: new Date(1000) )) // 1 second past epoch

Additional updates include fixes to the type compositor clone, ensuring types with default value of instance Date or Uint8Array are appropriately cloned as their instance types.

Related Issue: #670