Run unused functions reported by cppcheck
This change removes a few (but not all) unused functions.
Some unused helper functions were not removed due to their complexity and potential of future use.
When the 'flat' and 'trees' flags were moved into mgv6_spflags they
were left in mg_flags in an attempt to support old mgv6 worlds. However
their appearence in mg_flags causes confusion, also, later, old-world
support was found to be broken for mgv6 worlds with 'notrees'.
This commit cleans up the mess and comes a month after a thread warning
of the change, and explaining the required action, was posted in the
news subforum. Only old mgv6 worlds with 'flat' or 'notrees' are
affected, a small minority of worlds, the required action being
correctly setting these flags in mgv6_spflags.
Disable a section of the 'map settings manager' unit test which is to
be changed as it is causing problems for pull requests.
This commit refactors the majority of the Mapgen settings system.
- MapgenParams is now owned by MapSettingsManager, itself a part of ServerMap,
instead of the EmergeManager.
- New Script API functions added:
core.get_mapgen_setting
core.get_mapgen_setting_noiseparams,
core.set_mapgen_setting, and
core.set_mapgen_setting_noiseparams.
- minetest.get/set_mapgen_params are deprecated by the above new functions.
- It is now possible to view and modify any arbitrary mapgen setting from a mod,
rather than the base MapgenParams structure.
- MapgenSpecificParams has been removed.
