README.md: transform index entries into real links
README.md: add more git-related links
README.md: make a list out of the git section

Otherwise, the result on screen is not so pretty.
README.md: provide links for REST and CRUD
README.md: below JavaScript, also link to IFFE
README.md: make sure the title is all in Italian
README.md: also add link to Node.js API
Add node.js code snippets
node: correct whitespace errors and missing last newline
Add d3js exercises
Merge pull request #3 from bassosimone/patch-3

README.md: misc editing that does not touch git and node sections
Merge pull request #4 from bassosimone/patch-4

README.md: take care of the git section
Merge pull request #5 from bassosimone/patch-5

README.md: edits concerning the node.js section
Rename node to nodejs

As requested by @alferx, let's move all the files into
the nodejs directory.
Merge pull request #6 from bassosimone/patch-6

Add the node.js code snippets
Merge pull request #7 from giuseppefutia/patch-1

Add d3js exercises