Increase number of custom_property items

[verviers]

Numbers for "custom_properties" can be set from 0 to 9 now.

custom_property_0=
custom_property_1=
custom_property_2=
custom_property_3=
custom_property_4=
custom_property_5=
custom_property_6=
custom_property_7=
custom_property_8=
custom_property_9=

Need a bit more options. Is it possible to increase it at least until 20?

[void]

I will consider adding support for more custom properties.

Thank you for the suggestion.

[verviers]

Thanks! Will be waiting the feature in order to process some files with multiple differently named streams. Awesome support as usually.