Spaces in Objective-C and Objective-C++ files

I can't build anything in Obj-C or Obj-C++ if there are spaces within the filepath, which are valid (at least in Unix-based systems AFAIK). I get the following running the hello.m or hello.mm scripts:

`clang: error: no such file or directory: 'first_part_of_path_before_space'`
`clang: error: no such file or directory: 'second_part_of_path_after_space'`

This can be fixed with quotes around the filepath as done with the C and C++ ones or by escaping spaces. You can see the default builds [here](https://github.com/rgbkrk/atom-script/blob/master/lib/grammars.coffee). I tested both in a terminal and they seem to work.

Running 3.8.3 on OS X 10.11.6, Atom v1.8.0.