Remove ACE_INCLUDE_CONFIG_DIR

Looks useless now, it was here for compatibility with YARP 1
Use ace/config-windows.h instead of ace/config-win32.h

This is to avoid problems with 32/64 bit if it should change in the
future.
[Cleanup] Close bracket
Unset the right variables

Also use unset command instead of an empty set
Add missing PlatformStdlib.h include

For some reason it works everywhere without it, exept on MSVC in debug
mode.

Fixes #69