Small fixes where the `get_svg` function is used, for example,
in the (obsolete) `DrawingView` class and `Arch_SectionPlane`.
Also update the unit tests accordingly.
Remove unnecessary comments; as long as the variables
and functions have a clear name, they are self documenting,
so they don't need additional comments.
Clarify the import of IfcOpenShell's `geom`.
In some cases it fails importing and initializing the regular way,
`import ifcopenshell.geom`.
But it works in this way
```
from ifcopenshell import geom
geom.settings()
```
Some tooltips are made more readable by adding newlines.
For `IFC import`, better tooltip for the `Number of cores` option;
also the `Replace 'Project'...` option.
For `IFC export`, better tooltip for the `Export type`;
also `IFC file units`.
Also add `General options` in case other options are added.