MT add new column sigmaMw catalogue matrix

[Giuseppe Vallarelli]

[et=1]
[at=1]

It's necessary to add a new column to the catalogue matrix, this column will contain data regarding sigmaMw contained in earth quake catalogue. This addition will require to update the create_catalog_matrix job as well as EqEntryReader class.
When the sigmaMw is read by the earthquake catalogue its value is checked to be a valid one, if not valid a default value is placed instead. The default value needs to change from empty string to 0.0