Adding matrix based interface for PCA transformer.
Adding matrix based interface for PCA transformer.

etrain/keystone,kcompher/keystone,kcompher/keystone,tomerk/keystone,dongjoon-hyun/keystone,etrain/keystone-old,o0neup/keystone,tomerk/keystone,shivaram/keystone,javadba/keystone,amplab/keystone,etrain/keystone,amplab/keystone,shivaram/keystone,zhaozhang/keystone,etrain/keystone-old,tomerk/keystone,tomerk/keystone,o0neup/keystone,amplab/keystone,javadba/keystone,dongjoon-hyun/keystone,amplab/keystone,zhaozhang/keystone