GCC was warning about possibly uninitialized variables. Initialize them
and use values which are nonzero and distinct from each other and any
real value passed to any set method. This should prevent any false positives
from zero initialization.
Changed copyright end year to 2020 in every reference "Copyright (c) 2006-XXXX, assimp team".
Changed copyright end year to 2020 in every reference "Copyright (c) 2006-XXXX, ASSIMP Development Team".
Changed copyright end year to 2020 in LICENCE.rtf.
Changed copyright end year in CMakeFiles.txt files and any other places referencing Assimp with a copyright start and end year.
