Compile error on win7 64bit

[viney]

$ go build

github.com/karalabe/hid

In file included from .\hid_enabled.go:40:
./hidapi/windows/hid.c: In function 'hid_enumerate':
./hidapi/windows/hid.c:431:5: warning: 'strncpy' specified bound depends on the length of the source argument [-Wstringop-overflow=]
strncpy(cur_dev->path, str, len+1);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./hidapi/windows/hid.c:429:11: note: length computed here
len = strlen(str);
^~~~~~~~~~~

[dolmen]

This is not a compile error but a warning.

This should be fixed by upgrading hidapi. See #35.