SWORD defaults for option filters - the difference between additive and subtractive filters

There's a strange inconsistency in the way that SWORD handles some option filters in that it does not treat some subtractive filters properly in terms of defaults.

The following are subtractive filters, and the default for each should be to show the module text without stripping any feature thereof.

• UTF8ArabicPoints
• UTF8ArabicShaping (undocumented except in diatheke)
• UTF8Cantillation
• UTF8HebrewPoints
• UTF8GreekAccents

Most other filters are additive, so the default should be not to display the extra feature in the module.

Even for diatheke, the default should be to output the module text without stripping anything. The CL options for each of these subtractive filters should be redefined such that they must be specified to exclude these from the output rather than to include them.

Above all, there needs to be consistency.

And as this is an issue regarding defaults, it seems also that the way SWORD currently handles OSISVariants and ThMLVariants is inverted.

e.g. If in Xiphos, the user selects Primary reading, the Secondary reading is displayed, and vice versa. This needs fixing along with the requirement to support more than two variants.