Fix the compilation of I/O helpers

This MR fixes a few compilation issues caused by the recent migration of the "World" volume from GeoPhysVol to a more general GeoVPhysVol.

Related to !213 (merged) and #62 (closed)

added GeoModelIO GeoModelIOHelpers labels

mentioned in merge request !211 (merged)

added 3 commits

• 6f1e9238 - Change behavior of I/O helper functions, add a new 'getReader'helper.
• 14db7f62 - Update the HelloGeoRead example with the use of the new I/O helpers.
• 0dce221f - removing the old example

Compare with previous version

I have updated loadDB. Also, I added a const to that and to buildGeoModel. You are right, we could and should have const on the public loader methods.

I then remove the constness in visualization only.

Now working on the saveDB.

added 1 commit

• 2a0bfc75 - Add constness to methods loading .db and returning 'world'.

Compare with previous version

It looks like the pipeline failures are related to the changes in this MR. @rbianchi, could you please have a look? Thanks.

resolved all threads

added 1 commit

• 53a44dae - Fixed compilation of Tools, Examples and FullSimLight

Compare with previous version

mentioned in commit f2392d69

merged

mentioned in issue #96 (closed)

mentioned in merge request !219 (merged)