- Upgraded ImGui framework to 1.61 WIP, which adds a few improvements to context management.
- Removed from plugin implementation all the references to default ImGui context.
- Removed from ImGui Context Proxy destructor code switching to default ImGui context (there is no default context and decision is left for a higher level manager when to switch and to what context).
- Added own font atlas that is shared by all contexts and used explicitly to create Slate resources.
- Removed from ImGui Context Proxy workaround that was previously needed for copying cursor data to dynamically created contexts.
- Removed explicit saving of context settings before its destruction as this is now handled in ImGui::DestroyContext().
- Reimplemented ImGuiImplementation::GetCursorData() to use new interface.
- Added to ImGui Context Proxy a name that is mapped to ini file set in ImGui context.
- ImGui Context Manager generates unique context names from world type and context index.
- Refactored ImGui Context Manager to have a cleaner separation between editor and non-editor bits.
- Fixed context update rules in ImGui Context Manager.
- Changed widgets management in ImGui Module Manager to allow automatic garbage collection after viewports are closed and manual removal when module is shutting down.
- ImGui Widgets are in full control of communication with context proxies.
- Added basic world context utilities.
- Refactored world context index utilities and replaced ambiguous 'default context index' with 'editor' and 'game' ones.
- Added ImGui Context Manager to create and manage ImGui Context Proxies.
- Changed ImGui Context Proxy to dynamically create context and allow pairing with input state.
- Changed ImGui Module Manager to create one widget per context.
- Changed ImGui Widget to work in different input modes.
- Changed ImGui Input State to allow partial reset (only mouse or keyboard).
