Version 2.7.1 - Added support for book scanners utilizing 2 digital cameras

In version 2.7.1:

- Images of 'odd' and 'even' book/document pages may be in different folders. Use Input->Folder option and check box 'Odd and even pages captured using two cameras'. Fopydo will automatically re-order pages in correct sequence. If this option is used, leave the default Two-sided->Not applicable in the Image sampler directives pop-up.

- This function was implemented to support book scanners equipped in 2 digital cameras - one camera for capturing odd pages and one for capturing even pages.