client tracks current AVU list too zealously

[d-w-moore]

Every modification to the AVU list of an object currently calls _reset_metadata to set the _meta attribute to the current list of AVUs.
This is potentially inefficient for large AVU lists.

We probably can make the _meta object refresh lazily instead.

[korydraughn]

We should also consider giving control to the caller and letting them decide if/when the list should be refreshed.

[d-w-moore]

We should also consider giving control to the caller and letting them decide if/when the list should be refreshed.

In essence i think that's what we accomplish by making the repopulating function lazier