Remark with date stamp

The GC lines for 1.7u40 with the remark phase add a timestamp in the log like: 

    2013-09-09T06:45:45.825+0000: 83146.942: [GC remark 2013-09-09T06:45:45.825+0000: 83146.943: [GC ref-proc, 0.0069100 secs], 0.0290090 secs]

This fixes that (and also brings in the PringGCCause string stuff too)