apps: Call link_directories for LittleCMS2
apps: Call link_directories for LittleCMS2

The bundled library sets LCMS_LIBRARIES to a full path, which means this call is redundant (but should be harmless)

However external installs might set LCMS_LIBRARIES to just the library name ("lcms2"), so the link_directories call is important (as is the case with `brew install littlecms`)

Closes #215

AcademySoftwareFoundation/OpenColorIO,AcademySoftwareFoundation/OpenColorIO,AcademySoftwareFoundation/OpenColorIO,AcademySoftwareFoundation/OpenColorIO,AcademySoftwareFoundation/OpenColorIO