AMEGO-X mass model etc used up to the blue team review; includes astr…

…oPix & readout fixes but not Carolyn's updated mass model

AMEGO-X detector as of December 2020, to be used for first round of s…

…cience simulations

this is the AMEGO probe version used for the decadal white paper and RFI

Merge pull request #2 from ComPair/CarolynGeometryUpdates

Carolyn geometry updates