FR: Timing progress

[Paebbels]

Implement timing closure progress tracking. Several steps report an estimation of the current timing closure.

INFO: [Physopt 32-619] Estimated Timing Summary | WNS=-0.733 | TNS=-0.936 |
INFO: [Physopt 32-603] Post Physical Optimization Timing Summary | WNS=0.152 | TNS=0.000 |
INFO: [Place 30-746] Post Placement Timing Summary WNS=-0.733. For the most accurate timing information please run report_timing.
INFO: [Route 35-416] Intermediate Timing Summary | WNS=0.151  | TNS=0.000  | WHS=-0.136 | THS=-1.592 |
INFO: [Route 35-57] Estimated Timing Summary | WNS=0.177  | TNS=0.000  | WHS=0.115  | THS=0.000  |