gp4prog: convert some printf calls into LogError, where appropriate.
gp4prog: convert some printf calls into LogError, where appropriate.

azonenberg/openfpga,rqou/openfpga,azonenberg/openfpga,azonenberg/openfpga,azonenberg/openfpga,rqou/openfpga,rqou/openfpga,azonenberg/openfpga,rqou/openfpga,rqou/openfpga