Add texts and artworks in "Innovation" page

This pull req can be previewed live here:
http://bitcoininnovationimg.us.to/en/innovation

**Few changes in the text**
The introduction text has been replaced.
The "Automated solutions" text is new (replaces "Worldwide collaboration")

**New presentation pictures for each text**
Those pictures are from stock pictures sites, known Bitcoin projects, and Creative Commons Flickr users. I took care to ask / verify that we have sufficient permission to use these materials & provide required attributions and copyright notices on the page as well as in the COPYING file.

**No Retina support for now**
I have tested fallback high-res pictures for retina displays. While it works well and is generally well optimized, those devices would download 1Mb of data in total when visiting this page. I would abstain testing the limit of GitHub pages free bandwidth. So, this improvement is postponed for now.