New action: Add images to contact sheets

[Adam Reichold]

Attached is an implementation of an action to add the selected images to contact sheets using the given number of rows and columns. The layout itself is a simple grid into which the images are scaled using PIL with their original file name written underneath them. Persistent state such as the current canvas is stored in the action cache.

Please consider reviewing the action and distributing it with the upstream source or using Phatch's wiki. Thank you.

[Adam Reichold (adamreichold)]

I am sorry, but while trying to clean up the code, I rather introduced a bug into it. Hence here is a revised version that also allows to customize the caption using Phatch's variable replacement mechanism.

[Adam Reichold (adamreichold)]

I fixed the usage of ImageFont.truetype and added an parameter to optionally rotate images to better fit the uniform grid.