[png-mng-implement] Framework name in libpng/CMakeLists.txt

[Glenn Randers-P. <gl...@gm...>]

Cmake gurus:

I've received a suggestion that the framework name in libpng/CMakeList.txt
should
be "OUTPUT_NAME Png" not "OUTPUT_NAME png".

Should I make the change?  If so, in libpng-1.6.18 or wait until 1.7.0?

Glenn