Merge pull request #44 from coolwanglu/incoming

simply async callback functions
1.22.2
Update SIMD.js code generation due to API update
Handle the undef vector types.
1.23.0
Merge pull request #45 from huningxin/incoming

Update SIMD code generation due to simd.js update and fix the undef handling
1.23.1
align the current stack frame to something larger than the default, when necessary
emit a string describing why code cannot validate, when it can't