SSd geometry update

The SSD geometry also have quite apperent problems,- many steps through volumes.
I found several volumes that are the final but declared many 
Started revisiting Nov 2, continued Nov 9.

- Made the SFMO into an only Volume; placed it at the outer radius of the OSC.
- Change the  SFLM to be a TUBS just as for PXL, and IST
- Got rid of the  SFSM and SFDM mother volumes and place the lower level directly in the SFLM
using proper translation and rotation to get back to the old setup.

The ladder with the active part is still part of the SFSW (box) mother volume. and may thus be hidden to STI.

- checked that tracking at 90 deg and eta=0 produces same passing of material as previous version. Some the issue for SSD seems not to be missed material as for
IST but possible the many steps, or how STI implements the material.

- I note there are a good deal of small overlaps in particular relating to the volumes in particular
   SFFL and SFES SFEB all in order 170 and 140 microns. I suspect but do not know that these were also present in
   previous version, but since tagged as many they did not show up in the overlap check. Note these are mylar material, but named 
   big and small elbow; Not clear these are correct. I am tempted to take them out. (see pict 1 below)
- took SFES out  and now have only 11 tiny overlaps left

- The new tree structure is shown in the second figure.

The number of steps has been reduced tremendously - see figure below. Previous the same stepping would be about 3,000 steps each 100 micron

NOTE: The SisdGeo7.xml may need to change to  SisdGeo8.xml since the code as re-written cannot be used for any previous run period.
It is assumed that all ladders are placed identical and just rotated. Note from Jason, this apperently is not an issue. I may get rid of old pieces of code that
are only relevant for the previous incarnations.

This last figure shows the steps at 90 deg (muon)