Include 0AD's own mod.json

* Simplifies the mod dependancy calculation code slightly
Add dependancy lines for technologies

* If one technology requires another in the same building to be researched, a bezier curve is drawn between the two icons
Update mods' simulation data from their respective repos

Updated:
   - 0ad
   - han_china
   - millenniumad
Optimisation: `array_key_exists()` -> `isset()`

* Apparently, the builtin php funtion `array_key_exists()` struggles to deal with large arrays (> 200 entries)
   - The `$g_templates` array ends up with around 1106 entries, so... yeah.
* In these cases it's a lot faster to use `isset()`
* All instances of `array_key_exists()` have been replaced with `isset()`
   - This has caused parsing times to be decreased from 15/16s to just under 1s, roughly 15x faster