COMP: Failed comparision of stream to NULL

KWStyle/kwsXMLReader.cxx:33:14: warning: comparison between NULL and non-pointer ('std::ifstream' (aka 'basic_ifstream<char>') and NULL) [-Wnull-arithmetic]
  if (m_File == NULL)
      ~~~~~~ ^  ~~~~

Use m_File.fail() instead.
Merge pull request #3 from BRAINSia/FixC++11

COMP: Failed comparision of stream to NULL