Change interfaces to make geometry always explicit
Goes along with LHCb!3019 (merged), Phys!928 (merged), Moore!869 (merged), Analysis!794 (merged), Castelao!106 (merged), Alignment!185 (merged) and Panoramix!96 (merged)
Most interfaces using geometry were not passing it explicitely, relying on low level globals and caches to find out the right one by magic.
This is no more possible for at least 2 reasons :
- in multi-threading mode, several geometries may be in flight concurrently
- DD4hep requires explicit geometry passing
On the way, a fair amount of code refactoring was made, including :
- merging of .h into .cpp when possible
- cleaning up of unneeded code (e.g. many empty destructors)
- sorting out includes