First D3 chart rendered

.scrapbooks/example_d3_js.json is a working D3 in i.is example. To make
this happen a few changes were made:

* Dependency on d3 was added to make it avalialbe in the server REPL
* repl prompt was switched from ‘>’ to ‘@\n’ to avoid splitting HTML
output of repl by tag delimiteres
* Special inline marker ‘%’ was introduced, when used at the beginning
of the cell it suggests to render the output of the cell evaluation as
HTML
D3 example minor update
Support cell inlineMarker on save/load

inlineMarker needs special support on scrapbook save/load operations:
basically it says to use node’s .html(…) instead of .text(…) methods.
Minor d3.js example update
Minor d3.js example update
D3 example and screenshot updated.
README.md updated
...and some typos fixed.
Update README.md
Update README.md
Examples and screenshot were updated
Update README.md
Merge branch 'd3'