Remove limit of 10 data points per coordinate

[idantene]

This seems like a leftover from some debug or testing suite? :)

https://github.com/ecmwf/skinnywms/blob/master/skinnywms/fields/NetCDFField.py#L73

[sylvielamythepaut]

Hi Idan, Thanks and Yes, you are right. Removing the limit in the next version. Sylvie