Regression: No flag for skipping clearing logs and errors

[VonOgre]

Support for invoking PAL.ps1 without clearing the entire PS session log and errors collection was added when PR#12 was completed, but was lost during the release of 2.8.1.

If PAL is part of a larger automation script, it would be very valuable to have the option to not clear the entire log of execution up to the point of invocation, so that a user can see the full view of what their automation did.