delta_om: Delta om, returns delta omega and updated omega
In BenjiUvA/Learning_Ising_Model: LIMA data simulation

This function uses Hebb's rule to update omega. It returns the new omega matrix and a matrix with delta omega.

1	delta_om(omega, X, e = 0.001, lambda = 0.001)

`omega`	is a (symmetrical) matrix with the strength of connection between each nodes. Set the the diagonal to zero.
`X`	is a configuration of the network (e.g. if there are three nodes, c(-1,1,-1))
`e`	is the learning parameter (default setting = .001)
`lambda`	is the decay parameter (default setting = .001)