v1.63

use typed array set instead of emscripten::vecFromJSArray

update to Emscripten 1.38.10; fix compiler warnings; update npm packages

clean up using import/export/access templates

import_number_or_null for float

import/export number; import ImVec2/ImVec4 or null

clean up code with some macros

wrap ImGuiContext; move global variables

use opaque pointers for ImGuiContext

utf-8 support

AddFontFromMemoryTTF needs a native copy of the data

use optional_override instead of select_overload for lambda functions

fix indentation

change strcpy to strncpy

more font support; add fonts to style editor in demo

use raw pointer for ImGuiContext

move and rename all static globals

label reference get/set functions

remove some unused raw pointers

use references for ImGuiTextEditCallbackData and ImGuiSizeCallbackData

remove constructors for ImVec2 and ImVec4

import float where Number.MAX_VALUE might be used

initial Drag/Drop support

ImFontAtlas::GetTexDataAsAlpha8 is 1 byte per pixel

bind more of ImGuiIO

fix ImDrawList::AddTriangleFilled

add ImDrawList::AddPolyline and AddConvexPolyFilled

add ImGui::SetAllocatorFunctions

add ImGui::VSliderScalar

add and check ImGui::DebugCheckVersionAndDataLayout