Cost history numeric error

[poacherone]

When adding a cost that is above a million, Coral will add two commas to the line (only in the interface, it's not added to the database). But trying to edit the cost it gives an error: price not numeric.

This can be worked around by deleting the extra punctuation when editing (they will be added anyway), but is annoying nevertheless. Extra interpunction should preferably not be added to the edit cost page at all! Especially taken into consideration the different ways of writing larger numbers internationally, as with issue #311