Improving performance by reusing curl_get connection.  Adding backfill
support.

Signed-off-by: Chris Roblee <chris@playnomics.com>
fixed typo

Signed-off-by: Chris Roblee <chris@playnomics.com>
Initial version of a sample backfill client (appStart, transaction,
userInfo only)

Signed-off-by: Chris Roblee <chris@playnomics.com>