Remove ORC_[NOEXCEPT|NULLPTR|OVERRIDE|UNIQUE_PTR] macro usages

the following macros could be removed from the main source code to make the code neat.

```

#define ORC_NOEXCEPT noexcept
#define ORC_NULLPTR nullptr
#define ORC_OVERRIDE override
#define ORC_UNIQUE_PTR std::unique_ptr

```

These macros should only be keeped in the `orc-config.hh.in` for backward compatiblity(in case any user use these marcros).