Closes #39

Closes #80

The check if ( subdevice != -1 ) was being done on a potentially
uninitialized variable.

Use free() for allocated memory by calloc (not delete).
Deleting calloc-ed memory will become problem in the environment which
overrides global "operator delete" like some game engine.

Without algorithm header, Visual Studio complaints that std::max is not
declared and defined.
Including algorithm header resolves this issue.