collageformatter 7.x-1.0-rc5

Changes since 7.x-1.0-rc4:

• Implemented #2294443: Collage layout - added individual class for every image wrapper
• Added theme layer and templates
• Changed default original image reference option back to symlink.
• Implemented #2299701: How to limit the height? - added height limit for the collage
• Implemented #2306863: Do not upscale images in collage - added option to prevent images upscaling
• Calculation improvements