Saturn dromajo

[jzhou1318]

Add Dromajo support for the old version of Saturn-V.

• toggle Dromajo simulator settings to match the settings of the Saturn-V. core

Depends on changes made in:

https://github.com/ucb-bar/saturn/pull/26

• Construct trace signals from the Saturn-V core. (for use in Dromajo).

ucb-bar/testchipip#182

• make a new ExtendedTracedInstruction to encapsulate the signals needed to be passed out of the Saturn core.
• Pass the signals from the Saturn core
• reorder out-of-order instructions from Saturn-V. through a buffer and pass the re-ordered instruction into the Dromajo simulator

[et-tommythorn]

Changing the semantics of M like this would break existing usage. You could make it accept both 0x-prefixed hex and decimal otherwise.