Format.Filter.v1 may fail to read LowerBoundary and upperBoundary

[elemoine]

Format.Filter.v1 fails to correctly read LowerBoundary and upperBoundary if the value is 0 and it is included in a Literal tag.

E.g.

<ogc:LowerBoundary>
    <ogc:Literal>0</ogc:Literal>
</ogc:LowerBoundary>

Patch to come.

[elemoine]

See patch-2696-A0.diff . Tests pass in FF3, Chromium6, and IE7. Please review.

[bartvde]

Good catch, looks good, please commit.

[fredj]

r10420