(svn r14332) -Fix[FS#1885]: Balance the monthly random industry changes, by introducing a daily random industry change.

This will allow to perform more changes per month on big maps and less on smaller maps, while not overtaxing the IndustryMonthlyLoop process.
Thanks to frosch, for nice code ideas and rewrites

src/industry.h

@@ -260,6 +260,8 @@ static inline IndustryGfx GetTranslatedIndustryTileID(IndustryGfx gfx)
 
 /* smallmap_gui.cpp */
 void BuildIndustriesLegend();
+/* industry_cmd.cpp */
+void SetIndustryDailyChanges();
 
 /**
  * Check if an Industry exists whithin the pool of industries