Fix aircraft xml descriptions

Closes #5 and #3

• deletes description options that we don't have as configurations (LH2 and BWB)
• deletes options that do not work (true of aerodynamic_technologies)
• fixed typos (missionData in mission_data etc.)
• include switch and selector
• delete tank ID 5 and 6 (additional center tank and trim tank) as aircraft-design!31 (merged) allows overshoot (have not tested it though)