Merging PR #45: Fix deprecation warnings in IsBindable.
Replaced FKey::IsFloatAxis and FKey::IsVectorAxis calls with the corresponding FKey::IsAxis[1|2|3]D method calls.
Background: FKey::IsFloatAxis and FKey::IsVectorAxis are marked as deprecated as of UE4.26, replaced with FKey::IsAxis[1|2|3]D methods.
- Removed explicit PCH.
- Fixed includes to compile for all supported engine versions, including non-unity builds.
- Configured build.cs to treat ImGui as an engine module and added stricter compilation rules.
