FMC Updates

[remenkemi]

Simconfig rewrite (saves aircraft configs/settings) Fix POS and PERF init page bugs Lots of FMC bug fixes Fix #74

[remenkemi]

TODO:

• [x] Load nearby navdata on aircraft load so entering REF AIRPORT works first try
• [x] Allow DRAG/FF to be set without a leading zero (ex. entering .5 rather than 0.5 should still be valid)
• [x] Clear scratchpad after arming DRAG/FF entry ("ARM" stays in scratchpad)
• [x] Readme popup not working on Windows
• [x] Can't copy REF AIRPORT coords when LAST POS is nil
• [x] Whatever is going on with PERF INIT
• [x] Shorten output spam to make it easier to read
• [x] Fix EICAS fuel unit conversion
• [x] Set up Stack Trace Plus
• [x] Test bruh's plugin
• [x] #74
• [x] clear scratchpad when entering DRAG/FF

ETA: June 15

Will either work on standby horizon, performance pages, or RTE pages next. If EFB textures are ready, I can start on that as well.