write neurons save metadata by default

[dokato]

Quick suggestions: could write.neurons save data.frame by default (i.e. include.data.frame = TRUE), or is there any reason why it defaults to F?

I missed that parameter and was forced to redo my neurons download (~20min) just to retrieve the lost metadata.

[jefferis]

I guess it could. I suppose I was just being conservative, because until now people have mostly been using to save an SWC zip file to distribute as supplementary material.