Inspect the code base and fix deprecations

[lancelote]

The plugin now uses the 242 platform (since #295), but I didn’t change any code as it was working fine. There are a ton of deprecations, though. Find & fix them

[elmot]

FYI: Branch (elmot/nova-243)[https://github.com/JetBrains/intellij-micropython/tree/elmot/nova-243] is compatible with 243, all the deprecated API is dropped