Cleanup followings:
elfFile.{hpp, cpp}, elfStringTable.{hpp, cpp}, elfSymbolTable.{hpp, cpp}, elfFuncDescTable.{hpp, cpp}

1. Used wrong style, e.g. using m_member instead _member for member variables.

2. Some os specific code in shared code.

3. Kept section header string table, which not used for decoding functions.

4. Implementation tried to access file directly for symbol, string etc. when cache is not available (due to lack of memory), but it never worked. Since when failed to allocate cache, it set status code to out-of-memory, put decoder in error state and never tried to fulfill the request.