Tracking spec level support

[brianjmiller]

Just opening this issue as clearing house for what is and isn't in yet towards spec compliance.

Requirements:

• Bump version list
• Context Activities as arrays
• deprecated 'voided'
• Add Statement 'version' property
• Query API (authoritative removal, mode expansion)
• Fetch voided statements
• Anonymous Groups
• Document merge/partial updates (State, Activity Profile, Agent Profile)
• Statement attachments
• Statement signing
• Fetch of URL related items