Fixed the object check in binary.removeBlobs

Remove blobs has to iterate over a javascript object and asynchronously
remove the blobs / files. It does this by iterating over arrays and
objects in the larger object recursively.

Problem was in checking for object to iterate over, wasn't checking if
that object was binary data itself. So it was working, but really slowly,
by iterating over every byte in a Buffer and checking it for blobs.
Much faster now :)
Removed has-binary-data dependency

And replaced it with better isBuf function. Has binary data would not have
checked objects that contain blobs. isBuf only checks the current object,
not its child objects