Return 0 instead of null in number filters (unless the value is NaN)

[kcaran]

I'm having issues sorting with negative numbers, both integers and floats. The parseInt and parseFloat filters are returning 'null' instead of zero, so zero values are separated from the non-zero values.

Instead of

-4 -2 0 0 1 3

I get

0 0 -4 -2 1 3

[mattiash]

Thank you!