Support reading Microsoft /Date(123456789)/ Timestamps

[James Powell]

Microsoft uses a JSON Timestamp format of Unix milliseconds in a /Date(1323232441424)/ string.

Used, for example in the Windows powershell command

Get-Process | select name,id, starttime | sort starttime -Descending | select -first 1 | ConvertTo-Json

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Support reading these timestamps, for interoperability with Windows.

[James Powell]

Moved to JDP Common Utilities Issue #2