Merge branch 'master' into ios-build-script

* master: (148 commits)
  Update Importer.cpp
  [-] Trace print removed.
  [F] Get return "like true" when error occured.
  [*] qt_assimp_viewer can be built with Qt4 or Qt5. [F] Working in doule precision.
  [F] List of importers can be empty.
  [F] More correct control by a mouse
  [F] React on mouse pressing ig view only.
  [F] One alignment for labels. [-] Unused checkbox.
  [+] QtCreator temporary file.
  [*] Refactoring of "draw axes" procedure. [-] Removed not working part of code for reloading textures. That do nothing, just show checkbox. As Yoda said: "Do. Or do not. There is no try."
  [-] Function "GetExtension" always return lowercase string. Using uppercase extension in desc is not needed.
  glTF/2.0: Pick scene zero as scene to recursively load if no "scene" property is specified.
  Fix GenVertexNormals
  [F] Wrong type in equation.
  [F] Uninitialized variables.
  Fix #1587 : add validation to LWS unit test
  Fix #1970: stl with empty solid
  Add test for issue 1970: STL with empty solid
  Add mesh name to ValidateDataStructure log
  Read and write the KHR_materials_unlit glTF/2.0 extension.
  ...

# Conflicts:
#	CMakeLists.txt
#	port/iOS/build.sh

.gitignore

@@ -12,6 +12,8 @@ build
 bin/
 lib/
 
+# QtCreator
+CMakeLists.txt.user
 
 # Generated
 assimp.pc
@@ -38,6 +40,7 @@ tools/assimp_cmd/Makefile
 
 # Tests
 test/results
+test/readlinetest*
 
 # Python
 __pycache__