reimplemented custom version of get_max_iso_packet_size, which works for usb 3 endpoints; this allows to switch from the forked libusb version of @JoshBlake to the latest official libusb version;
Merge remote-tracking branch 'christiankerl/fix_max_iso_packet_size' into mac_osx_fixes2

Conflicts:
	examples/protonect/src/libfreenect2.cpp
	examples/protonect/src/usb_control.cpp