Build flags tweak release..

This release has the following features:

 1) build flags were optimized with debug builds now have different flags than release builds.
 2) -Oz was done for compile-time
 3) -flto -gline-tables-only and -Oz was used for linking time
 4) debug builds are significantly faster now (but without the optimizations)
 5) wasm.br file size went from 4Mb to 2.8Mb, so significant improvement for browser load time
 6) I also tried other flags, unsuccessfully, so --closure 1 was not released to the public, since it failed to produce working
     version of the software
 7) wasm-opt has new pass in release builds, which tries to optimize it for code size.