[Setup] Validate the Long type traits in different compilers.
[Numeric] Fix: 64-bit integer literal should use "ll".
[Setup] Fix: Long is an individual type in Xcode/Clang 32-bit.
[Setup] (refactoring) Rearrange Compiler.h and CaramelPch.cpp
[Setup][Android] Fix: std::size_t in GNU C++ is Uint32/64.

- (refactoring) Remove redundant define CARAMEL_LONG_IS_INDIVIDUAL.
[Setup] Fix the type detection of std::size_t on Xcode/Clang.
[Test] (minor) Fix: Missing a typename.
[Setup] Add architecture detection in VC and GCC.

- Now can detect only two archs: x86 and arm.
[Setup] Detect x86 and arm on Xcode-Clang.
[Setup] (refactoring) Improve comments.