Revert "Read arraybuffer directly from HEAP and contert it with TextDecoder"

This reverts commit 6bb0e53afb72c5dd587e53fbd5098c043da8b75a.
change "std::sort" to "qsort" in order to reduce memory consumption
set predict_buf size to kMaxPredictNum (500) in pinyinime_dictbuilder.cpp
reduce code in testing phrase-prediction
change emscripten path in build.sh
add "libpinyin_js.patch" to improve "libpinyin.js" performance