Timing report enhancement

[marwaneltoukhy]

Some of the timing reports either don't make sense or needs to include more information; in reports/routing there's are two report parasitics_sta.wns.rpt and parasitics_sta.worst_slack.rpt that basically report the same thing, but the worst_slack report has more details on setup and hold slacks.

parasitics_multi_corner_sta.worst_slack.rpt should report the corner

parasitics_sta.tns.rpt should report both the corner and whether it's min or max (setup or hold)