Kill AppendSample interface definition.

AppendSample will be repcated with AppendSamples, which will take
advantage of bulks appends.  This is a necessary step for indexing
pipeline decoupling.

Change-Id: Ia83811a87bcc89973d3b64d64b85a28710253ebc
Kill interface cruft.

These pieces were never used and should be thusly removed.

Change-Id: I8dd151ec4c40b6d3ccffad1bb9b8b75a92e9ee37