Make age4builder export to RTS_Overlay

[LENpolygon]

Make age4builder export to https://github.com/CraftySalamander/RTS_Overlay

Notes by the dev:

From what I see, a few optional columns are missing:

• total population count
• total villager count
• age They are optional for my tool, but would still be interesting (in particular, the population total count is useful to follow BOs).

After that, exporting the code in a format for my tool should be pretty easy. What is mainly needed is:

• formatting a bit the text to have the correct JSON format
• using a dictionary to convert your pictures names to the names I am using (for instance 'Spearman' -> '@unit_infantry/spearman-1.png@').

[coreyjansen]

Agreed this would be amazing! I am thinking we could calculate the total pop count by adding how many villagers are on food, gold, stone, wood...