* Add build configuration for Mac
This patch implements Mac build basically based on Linux platform
implementations and configurations.
The document to build it on Mac has been updated as well.
* Update wasm_application.h
* Update lib_export.h
Add comments for the functions.
* Implement memory profiler, optimize memory usage, modify code indent
* Implement memory.grow and limit heap space base offset to 1G; modify iwasm build type to Release and 64 bit by default
* Add a new extension library: connection
* Fix bug of reading magic number and version in big endian platform
* Re-org platform APIs: move most platform APIs from iwasm to shared-lib
* Enhance wasm loader to fix some security issues
* Fix issue about illegal load of EXC_RETURN into PC on stm32 board
* Updates that let a restricted version of the interpreter run in SGX
* Enable native/app address validation and conversion for wasm app
* Remove wasm_application_exectue_* APIs from wasm_export.h which makes confused
* Refine binary size and fix several minor issues
Optimize interpreter LOAD/STORE opcodes to decrease the binary size
Fix issues when using iwasm library: _bh_log undefined, bh_memory.h not found
Remove unused _stdin/_stdout/_stderr global variables resolve in libc wrapper
Add macros of global heap size, stack size, heap size for Zephyr main.c
Clear compile warning of wasm_application.c
Enable setting external memory space for wasm app, the feature is disabled by default;
Remove wasm_application_exectue_* APIs from wasm_export.h which makes confused.
