Updated Cura profile for i3 w

[LLemon]

Hi,

I was having issues with the I3 profile for cura and after a little investigation, I found some bugs in the way the json was formatted.
I've fixed the json and my profile now loads in cura.
I adjusted the profile to use a .3 nozzle, because that's what my printer came with.

I'm attaching a zip of the repaired profile for all to use.