Collection of extensions from TuttleOFX: align, layers, lines, parallel, pattern, shrink, wuline

There is a collection of interesting extensions (and their tests) in repo of TuttleOFX project which uses Boost.GIL:

https://github.com/tuttleofx/TuttleOFX/tree/develop/libraries/boostHack/boost/gil/extension/toolbox

Most of them have been authored by Tom Brinkman, [a known author of GIL extensions](https://stlab.adobe.com/gil/contribute.html).

I think it is a good idea to review some of them and port/add to current Toolbox extension.