V1.0

* New text for the home page
* Announcement
* Extracted install instructions from getting started

/cc @alco @ericmj please review!
"lightweight threads"? I don't remember this term popping up in discussions. Can it not be "lightweight processes (not to be confused with OS processes)"? Neither wording explains what those processes are, but in the latter case we are at least not making up any new terms.