Added todo.
Added small notes about computers, terminals, and personal computers.
Added buzzword cloud.
Minor cosmetic  changes.
Added examples.
Minor cosmetic changes.
Made subsubsection* a subsection and added a ref to it.
Added conclusion.
Added (current) conclusion on the issue of doing recursion in advance,
doing pointers later, etc.
Added corollary.
Added some notes on "advanced" stuff.
Started Concurrency II: executors and concurrent collections.

Leaving Fork/Join for next year, as there will be changes in Java 8.
Added TODO.
More content.
More content.
More contents.
New version of publi.sh, more versatile and confortable to use.
Added TODO generic.
Added thread pools and concurrent data structures.
Added exercises for concurrency2.