[Ohrrpgce] SVN: teeemcee/11442 Progressively generated minimaps. Rewrote MapPreviewer to use them

[subversion at HamsterRepublic.com]

teeemcee
2019-11-29 21:21:21 -0800 (Fri, 29 Nov 2019)
500
Progressively generated minimaps. Rewrote MapPreviewer to use them

MinimapGenerator.run() takes number of seconds to generate for.

MapPreviewer (currently used by the map picker and 'Add map as copy of') has a
bunch of logic to decide whether to delay generation or start by rendering just
a small minimap in order to attempt to:
-not cause a framerate drop even on slow machines
-not cause seizures as you scroll through maps

The mapedit.instant_minimap_threshold config option is no longer used.
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U   wip/common.bi
U   wip/common.rbas
U   wip/custom_udts.bi
U   wip/loading.rbas
U   wip/mapsubs.bas