#332 basisproject: Fix update of template version.
#360 Add basisproject upgrade subcommand parser.
#360 Align parameter documentation of diff3 module.
#360 Minor basisproject improvements. Allow template argument to be relative to template installation prefix.
#301 Fix bug in applying presets of project template.

By inserting the --no<opt> options at the beginning of the list of preset arguments, they can be overridden by consecutive meta-options which enable multiple options at once.
Merge remote-tracking branch 'github/bugfix/#301-basisproject-create-full' into develop
Merge remote-tracking branch 'github/develop' into feature/#360-basisproject-upgrade
Fix basis template configuration (#301).

The basisproject tool automatically adds the --no* options for any not mentioned template option. The doc-rst template included also the config-depends, which has nothing to do with documentation generation. A template option dependency should be expressed using the 'deps' dictionary entry of the option which depends on another.
#360 Update basisproject commands in documentation.
Merge remote-tracking branch 'github/feature/#360-basisproject-upgrade' into develop
#360 Add missing template arguments to upgrade command.
#361 Add basisproject help command.
Merge remote-tracking branch 'github/feature/#360-basisproject-upgrade' into develop
Merge remote-tracking branch 'github/bugfix/#361-basisproject-help' into develop
Ignore QtCreator user settings (backup) files.
Enhance custom layout creation how-to.
#364 Fix addition of "full" preset argument to template configuration.
#364 Clean up load_config of basisproject.
#340 Move BASIS_BUILD_ONLY definition to more appropriate location and edit help.
#340 Remove BASIS_SYTEM_CHECKS option. Instead, perform these (required) checks only for the build of BASIS itself.