simplify initial prettify phase in EMCC_DEBUG=2
REMOVE use JSON in EMCC_DEBUG=2, and time results
add rapidjson
compiling early version of optimizer.cpp
use global singletons for common strings
refactor EMCC_DEBUG=2 code to reuse the normal mode code
write code to bridge js and native optimizers, serializing to json between then
handle just_split/just_concat when bridging js and native optimizers
avoid copy in Cache.get if already in the right place
infrastructure to build and use native optimizer
fix detection of filename in js optimizer running on chunk
optimizer fixes
error detection and comments handling in optimizer
enable optimizeFrounds as a native optimizer pass
set up infrastructure to test native optimizer in other.test_js_optimizer
end of the road for rapidjson attempt
minijson.h
get most of optimizer building on new minijson.h
misc fixes
get optimizer building and running without crashes