create base documentation (issue #59)

This version introduces multiple enhancements:

added whole description about how framework work on server side and some images with information from tracer

Details of additions/deletions below:
--------------------------------------------------------------

Added:      /docs/image/tracer1.png
Added:      /docs/image/tracer2.png
Added:      /docs/image/tracer3.png
Added:      /docs/image/tracer4.png
Added:      /docs/image/tracer5.png
Added:      /docs/image/tracer6.png
Added:      /docs/image/tracer7.png
Added:      /docs/image/tracer8.png
Added:      /docs/image/tracer9.png
Added:      /docs/image/tracer10.png
Added:      /docs/image/tracer11.png
Added:      /docs/image/tracer12.png
Added:      /docs/image/tracer13.png

Modified:   /docs/how_it_works.md
            -- Added --
                added whole description about framework working

Modified:   /docs/benchmark.md
            -- Updated --
                fixed numbers in tracer colors description