updated version number to 1.15 so the game actually knows what I did.

updated for 1.15

- Updated version number to 1.14.*
- Brought jet engine costs in line with vanilla again.

- now fully compatible with rt56
- fixed it not working with kaiserreich/redux

- small update to bring the stats of plane machine guns in line with vanilla again.

fixed incorrect values for some tank modules

updated for 1.13.5

fixed welded armour costing 8 xp instead of the intended 2

updated for version 1.13.*

- Changed engines so that instead of every upgrade costing 2xp, upgrading to the same engine count (e.g. 1 engine to 1 engine) now costs only one xp, while upgrading to a different engine count (e.g. 1 engine to 2 engines) now costs 3 xp.
- Adding MOI's to equipment now costs only 1 instead of 5 xp.

updated verion number to 1.12.*