cpu: Add a SynchroTrace replay model
SynchroTrace's trace replay is a 1-CPI timing model that interfaces with

the multi-threaded traces from Sigil to inject traffic into the detailed

memory model. The high-level description of the execution flow is in

src/cpu/testers/synchrotrace/SynchroTrace.hh
The following is included in this patch:

 * The main SynchroTrace trace replay file

 * SynchroTrace parser file which processes Sigil Traces into

   SynchroTrace events

 * A front-end python configuration script with a default two-level

   cache hierarchy.
Change-Id: I6c89894d95974d838bc9ee3b9e468a4032f6613a