project_prop_on_subset was not working properly when the property
values are not tagged as values but some other name. Added a new
argument for that.

Also notices that interp(prop_values::Vector{T}, space::OMAS.edge_profiles__grid_ggd___space)
had a typo in return call and would have failed.

In project_prop_on_subset!, when the dimensions of to_subset is
lower, then an interpolation is required. This commit adds an
option to choose between thin plate spline (:thin_plate_spline)
(slower, more accurate) and using KD trees (:kd_tree)
(faster, less accurate).

Quick bug fix

While doing thin plate spline method for interpolation, it is beneficial
to reuse the matrix calculations done if the same grid susbset is
being used. So just like sharing a KDTree object, we can share the
TPS_mats which is a tuple of matrices and vectors required for this
spline function.

Added option for reusing TPS matrices