Use maxPacketSize of Interface 0 for the buffer in getUsbStringDescriptor and getLanguages

[alexredko]

We can use max buffer size obtained from descriptor.bMaxPacketSize0() instead of 256 in these methods because internally they call controlTransfer on interface #0. This fixes #3 without manipulations with dirvers. Some devices require to use a buffer of size bMaxPacketSize0 only for control transfer.