Check and format inputs
Check and format inputs

Make sure the provided inputs are valid and automatically choose the
boundary condition depending on the provided `boreholes_or_network`,
if not specified by the user (this is simply for conveninence).

This also makes use of the `find_duplicates()` function introduced in
#81 to make sure the bore field is valid and the g-function can be
properly calculated.

MassimoCimmino/pygfunction