Changes in what a 3.1 ruleset can do

[cazfi]

There's support for including a datafile in section file format, but with freely selectable content, to a ruleset, for ruleset lua scripts to use. The idea is that the lua script can implement any kind of parser for the datafile.
At this time scripting API has single function, luadata.get_str(key), for reading from the datafile.

Feature #661635

Now the datafile can be provided by the scenarios too. Feature #822120.

So the ruleset might provide parser.lua, and individual scenarios using the ruleset can provide their own data.

[cazfi]

Support for better granularity or output values has been started by adding ruleset setting output_granularity. Feature #822932.

At the moment it affects only how client shows tile outputs (if output_granularity is 10, the digit shown is tens etc)

[cazfi]

Added unit type flag "NeverProtects" that ruleset can use to override unreachableprotects server setting for specific units. (Feature #809471)

[cazfi]

New extra remove cause "Enter". It's for the hut entering behavior; so that behavior is now defined separately from the "Hut" extra appearance cause. This makes it easier, and sometimes more correct, to have huts that are not placed by the map generator in the beginning of the game. Feature #802768.

[cazfi]

Added history_interest_pml ruleset setting. Feature #823245

Wit this setting, history values grows interest each turn. The idea is that older history of the equal original value is more important than recent history. By the interest mechanism older history has grown more interest than recent.

[cazfi]

Added AI trait "Builder" that controls how much AI wants to build buildings (instead of units) Feature #825086