Projection information

[kcpevey]

There are currently several potential locations for projection storage in the adhModel object.

• The adhmodel itself has a projection object.
• The adhMesh object inside of the adhmodel obj has a projection object.

These need to be the same projection, but there is reasoning for each object holding its own specification.

Additionally, the adhmodel object inherits from the annotators which allows for specifying a crs on init which isn't stored but is propagated in the other elements.

Having the crs in so many places causes confusion in usage codes. This needs to be implemented in a smarter way, perhaps as a property.