Add possibility to have unembedded GeoJSON.

[BibMartin]

Addresses #285.
Instead of having an embed option as @ocefpaf suggested, the user shall pass data=open(filename) if he wants to have the file embedded, and data=filename otherwise.

Note that the style_function cannot be applyed in the latter case, because the file won't be openned.

[ocefpaf]

Note that the style_function cannot be applied in the latter case, because the file won't be opened.

How difficult would it be to read the style from the file and still not embed? We do not need to do this in this PR, but I want to keep that idea around.

[ocefpaf]

I am not opposed to this pattern: read in dir(x), but I think hasattr(object, name) is more common? Any special reason for doing that?

[BibMartin]

@ocefpaf

I am not opposed to this pattern: read in dir(x), but I think hasattr(object, name) is more common? Any special reason for doing that?

I guess this has few importance ; I'm just a goldfish who forgot the clean syntax. Corrected.

Same as above. I see isinstance(object, dict) more that type(object) is dict. Again, not opposed, just curious.

This one is more important ; for instance, someone may be willing to provide an OrderedDict instead of a dict ; yet type(OrderedDict()) is dict is False while isinstance(OrderedDict(),dict) is True. So, your (official) syntax is better.

I've corrected both lines.

[ocefpaf]

I guess this has few importance

I just asked for shear curiosity. Sometimes I learn new things by asking 😉

So, your (official) syntax is better.

I suspected so, but haven't tested it. Good to know!

Thanks! Merging this...