The Support class allow getting the required number of neighbouring points of a given one.
It does so in a way that only expands the search area in directions where we are performing derivation.
Now linking to a newer version of openfpm_data as a fix in const-ness of some operators was required.
Also minor fixes to some other tests.

Possibility to get derivatives of Monomial and MonomialBasis objects has been added to allow for easy arbitrary derivative computation when building the RHS in the DCPSE linear system.
Monomial was also renamed from MonomialBasisElement.

Add check for right dimension of the set of neighbouring points w.r.t. the size of the monomial basis.

The Vandermonde matrix builder fills an EMatrix using a given multivariate monomial basis, the point the matrix belongs to and a set of neighbouring points.
Initial version of unit tests are present.

MonomialBasis allows generating the right exponent multi-indices to be used to build the Vandermonde matrix for DCPSE.
Updated openfpm_data submodule is necessary for a fix included there.