Merge branch 'master' into master

re-org ems mem allocator source codes, update prot_wamr.md (bytecodea…

…lliance#217)

Sync with internal feature (bytecodealliance#204)

Refine build script of zephyr product-mini, enable aot soft-float sup…

…port (bytecodealliance#188)

Fix block addr cache uninitialized issue in aot compiler (bytecodeall…

…iance#181)

Remove unused build folders (bytecodealliance#168)

Former-commit-id: 227d494
Former-commit-id: 375c1ac

Fix out-of-bounds read in wasm loader (bytecodealliance#156)

Enhance wasm loader and update build app document (bytecodealliance#147)