Multiple versions of the same tech

Hi. Another small thing. Unless I misread stuff, you already check for file overwriting and take the correct one the game would load.

Though if the same tech is re-defined in an differently named file (possibly because you didn't want to change the whole file or because multiple mods are merged to create the tree) the script will create different copies of the technology rather than choosing the one Stellaris would actually load. Afaik (tested it with a simple test mod), if there are multiple techs with the same key, the game will prefer the one coming from the file with the largest ascii value (z_xxxxxx.txt would be prefered over a_xxxxxx.txt).

Thanks for you great work again ;)