New project: echoplexus #100

* logo from https://github.com/qq99/echoplexus/blob/master/assets/echoplexus-logo.png resized to 130×130 and centered in 160×160
* license from https://github.com/qq99/echoplexus/blob/master/LICENSE
* introduction from https://github.com/qq99/echoplexus/blob/master/README.md (excerpt)

Echoplex is too good to wait for someone to do this in some months (even not sure), so here’s it! 
I would use »collaboration« as a more fitting description. @yuwash what do you think?