LTAPIAircraft::getLocalCoord returns wrong altitude

## Describe the bug
`LTAPIAircraft::getLocalCoord` passes `bulk.alt_ft` into [`XPLMWorldToLocal`](https://developer.x-plane.com/sdk/XPLMGraphics/#XPLMWorldToLocal), which expects meter, not feet.

## Expected behavior
Correct altitude.


## Technical Info
 - OS: any
 - X-Plane version: any
 - LiveTraffic / LTAPI version: any

## Solution
Pass in `bulk.alt_ft * 0.3048`.
