darwin: use detach kernel APIs for capture

When libusb_detach_kernel_driver() is called on the first interface, we use
the capture re-enumerate APIs to force kernel drivers to detach. On
subsequent calls, a counter is incremented to keep track of the number of
detach calls. When libusb_attach_kernel_driver() is called for the same
number of times, then we re-enumerate (reset) and let kernel drivers
re-attach.

darwin_kernel_driver_active() is changed to attempt to claim an interface
and return 1 only if a kIOReturnExclusiveAccess status is returned. The old
implementation which looks for a CFBundleID in the IORegistryEntry does not
seem to work in all cases.

darwin_reset_device() is aware of the capture status and will re-set twice
if capture mode is enabled: once to do a USB reset and again to re-capture.

Signed-off-by: Nathan Hjelm <hjelmn@google.com>