Fix Warnings raised during compilation

[MathewBensonCode]

Attempted to fix the warnings that would persistently come up when compiling. These are possibly a source of bugs.

Changes made include:j

• use String version of ImGui calls in DockspaceUIComponent
• Change Handle::Index from uint32_t to uint64_t because it is we are using it to represent a void* and as we are generally targeting x64 the system would warn about this conversion.
• Used static_casts to deal with enum-to-enum comparisons using different enum types.
• return default typed Node in Messenger.h
• Close off switch statements with a default clause.