It's not necessary to create HandleScope in v8 native binding functions,
because it's guarrenteed that the there is a upper HandleScope when the
native function is called. So unless we are urgent to free the handles,
not using HandleScope in native binding functions is a cleaner and safer
choice.
'finish-launching' is more like a OS X message name, and in atom-shell
it means initialization has done, so 'ready' seems to be a better name
and more easy to remember.
The 'will-finish-launching' event just represents the corresponding
message on OS X and is the same with 'ready' on other platforms, so we
keep its name to indicate that it's only useful for OS X specified
code.
