Add emscripten_async_wget2 with progress callback

Send request Post & Get with progress callback
Add sample HTTP using emscripten_async_wget2
Add comment,test,authors. Change indentation and comma space

Modify the indentation
Add Author
Add comment
Add test inside runner.py
Merge remote-tracking branch 'wolfviking/incoming' into incoming

Conflicts:
	AUTHORS
	src/library_browser.js
	system/include/emscripten/emscripten.h
wget2 docs
rename websockets tests
refactor networking code to start supporting multiple backends
define tempInt in asm
ensure a return when an abort happens in a function that returns something
fix test_exceptions
stub _ZNSt9exceptionD2Ev for the case where dlmalloc is included but not libcxx, to avoid an asm warning
Merge branch 'incoming' into asm_js_nomerge