Separate linux, windows and apple packaging.
Big refactoring of the whole superproject, rename variables, change directory, remove old useless stuff, etc.
Add BUILD_SHARED_LIBS options for all external projects.
Add VTK_USE_NVCONTROL option.
Pool common variable of external projects modules.
Update packaging for refactored superproject.
add Disclaimer
Avoid to ended wit a project-prefix directory when USE_SYSTEM_PROJECT is set to ON.
Introduce USE_GIT_SSH option, set to OFF by default.
set NVCONTROL alwsays to ON