new file:   src/ConceptDetectors/topside/compact/elements.xml

* Reparameterization of constants while keeping mostly true to original dimensions
* Removed tracking extension variable in favor of just having
trackerZScale variable, and set back to 1
* Added placeholder solenoid yoke and RICH detector detectors

Script currently throws 100 10GeV muons flatly distributed over eta, and
outputs to LCIO.

Also removed a couple constants from sieic.xml that are now unnecessary
with the removal of the lcgeo dependency.

With this comes some updates in the SiEIC directory...
* Updated compact description to latest SiEIC design
* Added `src` and `bin` directories
* Added start of a standalone python simulation script in `bin`
* Removed `run_example` script and `gps.mac` since they are no longer
needed