Test the inputs to the `make_path_array` function
and return `None` if there is a problem.
Now the make function accepts as input a `"String"` which must be
the `Label` of an object in the document, so it is easier to create
arrays quickly from the Python console.
Add the new parameters to the make function, `align_mode`,
`tan_vector`, `force_vertical`, and `vertical_vector`.
These properties were added to the proxy object in 0db11da9cf.
Add message deprecating the older call `makePathArray`.
Adjust the GuiCommand accordingly. Now it uses the commit
mechanism of the parent `Modifier` class so that the executed
functions are recorded in the Python console.
Clean up the `PathArray` class as well.
466751c7a8