Two minor fixes

[GastonZalba]

Hi, i made two minor fixes long long time ago, and here we are...:

• One is to allow builds using webpack in strict mode (the default behavior).
• The other is very especific. It's fow when a SRT has information from two (or more) differents Drones. If the later Drone had missing values than the earlier one, the script was failing. But this is avoided with a minimal check, and the geojson is now exported correctly. This is useful if you edit/mix videos from two Drones, each with their own SRT (in Premiere Pro, by example), and you export an single video/srt pair with the diferents formats. Added a test using a SRT with mavic 2 pro and RTK.

[JuanIrache]

Thank you!