Fix error loading LUT files with Turkish locale (#984)
Fix error loading LUT files with Turkish locale (#984)

In file parsing there are tests like Lower(x) == "spilut". However this was
using the locale dependent std::tolower, which for Turkish does not change
I to i.

Instead this implements a custom Lower() function which is not affected by
locale and so can be used for file parsing.

Signed-off-by: Brecht Van Lommel <d22bc6bad61129b636affa2511b3ce522cd74bb3@blender.org>

Co-authored-by: Patrick Hodoul <4b28f131a549aaad9baa1418bd813779c16561ee@gmail.com>
AcademySoftwareFoundation/OpenColorIO,AcademySoftwareFoundation/OpenColorIO,AcademySoftwareFoundation/OpenColorIO,AcademySoftwareFoundation/OpenColorIO,AcademySoftwareFoundation/OpenColorIO