v8: upgrade to v3.20.2
v8: reapply floating patches
src: v8 api upgrade wip
string_bytes: stop using String::AsciiValue

Debug builds of V8 now actively check that the string only contains
ASCII characters (i.e. doesn't contain bytes with the high bit set.)
src: abort() on fatal error in debug mode

abort() generates a nice core dump and makes it easy to catch fatal
errors in one's debugger of choice.
src: enable native v8 typed arrays
persistent-ify pbkdf2
persistent-ify node.cc
persistent-ify HandleWrap and ReqWrap
persistent-ify pipe/tcp/tty/udp constructors
persistent-ify crypto
remove unused node_stat_watcher.{cc,h} Persistent
persistent-ify tls_wrap
persistent-ify node_script.cc
persistent-ify node_file.cc