1. Fix misleading indentation warnings.
2. Fix creating a temporary const copy when iterating over a map (thanks to range analysis warnings)
3. Fix creating a copy when iterating over a range without reference qualifier (also thanks to range analysis warnings)
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.
If one of the MDL importer implementations throw an exception, the memory allocated at mBuffer may never be freed. This fix should prevent further memory leaks.
Added code to use Half-Life 1 MDL loader in MDLLoader.cpp.
Added Half-Life 1 MDL loader files to CMakeLists.
Added new options in config.h to use with Half-Life 1 MDL loader.