libpng: update to 1.6.1

libpng: update to 1.6.1

This attempts to fix [YOCTO #4060]  - connman-applet spews warnings, but with this one PNG images still don't work in weston :(

The ARM NEON option was added because the autodetection code in configure.ac is broken:

	/usr/lib/weston/weston-desktop-shell: symbol lookup error: /usr/lib/libpng16.so.16: undefined symbol: png_init_filter_functions_neon

License checksums update due to date and package version changes:

index e95d359..d86a7da 100644

(From OE-Core rev: e31ef0211c2cb18c322517a44b714895e51284e1)

Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>