Minor re-balance. For Apocalypse mode.

1. Refactor: use MapUtilities logic for variation fractals instead of RND for ice shelf and borders. Aesthetic. No impact.
2. Bugfix: more grassland
3. Better configuration of global params. Mod if enabled will not effect regular gameplay.

1. Minor bugfix to GS ice shelf generation. It is more consistant in both GS and R&F/Standard Rules.

1. Support for GS Climate system (notably river flooding).
2. Tidy up/refactoring of terrain and feature generation to consolidate both the GS and standard versions of the maps. (Considerable divergence due to the addition of floodplains on grassland and plains in GS).

1. Reduce number of lakes to balance larger river network.
2. Bug fix for random World Age.

Fix reef gen. for R&F: northernly reefs only.

1. Add support for R&F.
2. Add southern ice at pole.

1. Adjusted terrain for a less hilly/flatter continent by default.
2. World Age and Rainfall are hooked up as advanced map options.

Code tidy up to allow for more natural wonders

1. Tidy up terrain generation. Added a touch of snow to Patagonia.
2. Allow lakes to be river sources.