Use libusb-compat instead of unmaintained libusb

I had problems building libusb on OS X Yosemite. `libusb-0.1` has not been updated for years, but there's a compatibility layer called `libusb-compat` that wraps around `libusb-1.0`.

```
 libusb-compat-0.1 is a replacement for libusb-0.1. However, instead of being an actual implementation, libusb-0.1 is more of a compatibility layer (or wrapper) which just converts libusb-0.1 calls into their libusb-1.0 equivalents.

It aims to look, feel and behave exactly like libusb-0.1. As it is a replacement, you cannot install it alongside libusb-0.1 on the same system.

As the compatibility layer implements the exact same ABI and API, no modifications to existing libusb-0.1-based applications are needed. You do not even have to recompile them. This compatibility layer is a drop-in replacement. 
```