Convert number arrays that have been stored as strings back to numbers.

[david-deboer]

We are in the process of updating hera_mc such that we can handle float arrays -- previously sqlite had been an issue. There are other arrays in the database that can be converted back to numbers. For instance, in antenna_status the 'histogram' and 'eq_coeffs' entries could be converted. Note that the current fix only handles floats, not ints, however that should be straightforward to add.