CMake: Ensure that CMakeFiles/Dictionaries/ exist
CMake: Ensure that CMakeFiles/Dictionaries/ exist

This is workaround for older CMake not creating target directory
for custom commands.


Former-commit-id: 9e286fc871f8fa68809f7a71160c029bf2c9ecb8
wkrzemien/j-pet-framework,wkrzemien/j-pet-framework,JPETTomography/j-pet-framework,alexkernphysiker/j-pet-framework,JPETTomography/j-pet-framework,wkrzemien/j-pet-framework,alexkernphysiker/j-pet-framework,alexkernphysiker/j-pet-framework,alexkernphysiker/j-pet-framework,wkrzemien/j-pet-framework,wkrzemien/j-pet-framework,alexkernphysiker/j-pet-framework,JPETTomography/j-pet-framework