File: declare and implement class auto_buffer
File: replace CAutoBuffer usage with auto_buffer, fixes memory allocation check
File: add 'LoadFile' function and copy code from FileUtils
CFile::LoadFile: replace ugly reference to pointer with auto_buffer
FileUtils::LoadFile: replace implementation with call of CFile::LoadFile
[vfs] CFile: remove 'virtual' from destructor
no class is derived from CFile
[vfs] CFile: fix: close underlining file implementation in destructor