* Use "L" notation for wide character

* Remove unneeded cast

PrintMessage() now uses const pointer

* C++11 accepts std::string for std::wifstream

* C++11 accepts std::string for std::wifstream

* Use mbstowcs()/wcstombs() to convert character class

This fix works when file path includes non-ASCII characters.

* Revert "Use mbstowcs()/wcstombs() to convert character class"

This reverts commit 7fd150a1570b8d6de246da352688daaeadcda998.

mbstowcs()/wcstombs() is not so secure, and recommends mbstowcs_s()/wcstombs_s().
But these secure variants are not supported by some C libraries.