Use NLopt C API

Author: MuTsunTsai

Diff for: lib/README.md

@@ -8,9 +8,8 @@ Those including:
 
 - Bootstrap: Customized [Bootstrap](https://getbootstrap.com/) theme for BP Studio.
 - LZMA: The released file by [LZMA.js](https://github.com/LZMA-JS/LZMA-JS) contains minification error which makes it unusable, the file here fixed the error.
-- NLopt: This contains the precompiled [NLopt](https://github.com/stevengj/nlopt) static library and header files.
+- NLopt: This contains the precompiled [NLopt](https://github.com/stevengj/nlopt) static library and header file.
   Note that this is a specially compiled version that runs only the SLSQP algorithm and nothing else.
-  We have also modified nlopt.hpp to disable exception throwing.
 - Optimizer: The compiled WASM files of the optimizer.
   There are two build variants:
   1. Debug build is for running in Node.js and for mocha unit tests