build: fail w/err msg when missing binutils

Building --with-dtrace requires objdump from GNU binutils.
This change inserts a helpful error message if there is a
problem executing objdump.
net: fix bufferSize include writableStream length

socket.bufferSize missed to include the length of internal buffers in
writableStream.
typed arrays: replace switch with templates

Convert TypedArray's TypeName implementation to template specialization
instead of a switch() statement.
typed arrays: don't declare as module

TypedArrays is not a module, it is attached to the global object.
Don't register it with Node's module system.
doc: os.cpus() returns times in milliseconds
stream: Add readable.push(chunk) method
net: Use readable.push() instead of private methods
stream: Use push() for readable.wrap()
http: Use stream.push() instead of touching _readableState
http: Don't switch the socket into old-mode