KV Provider / Prepared Query Bugfixes

[djtaylor]

This adds a new KV provider for accessing the Key/Value database API. This also attempts to address issues in the previous Prepared Query PR and the following issues:

• New prepared queries provider not accepting integers #291

[djtaylor]

Initial testing seems to confirm that the following works:

• Create a new KV object
• Update an existing KV object
• Delete a KV object
• Handle the 404 when no KV objects exist for the DC

EDIT:

• Add support for flags parameter w/ default value

[solarkennedy]

Whoa! Thanks!