SCHMEA-17 DeleteTool replaces and improves DeleteTableTool

Signed-off-by: Robert Chu <robert@wibidata.com>
SCHEMA-128. Add minimum size option to KijiTablePool.

The option to require a minimum table pool size is added in this commit.
Kiji will aggressively open the min number of connections the first time a
table connection is requested and will maintain at least that size of a pool
indefinitely.

Signed-off-by: Milo <milo@wibidata.com>