Fix compilation w/ GCC4.8... -Werror=narrowing

Change-Id: I232b40df44f5d2e30f5a2aa013c2286628e7f1a1
libcopybit: fix for narrowing conversion in C++11.

Change-Id: Ic73a3c94b5142d35e0912f98acaa3d0c98163e0a

Conflicts:

	libcopybit/copybit_c2d.cpp