IsWin64() to be renamed as IsExe64()

[Antonio Linares]

In next FWH 13.07 we will rename IsWin64() as IsExe64(), as this function was checking if our app is 64 or 32 bits.

From FWH 13.07 on, IsWin64() will check if we are on a Windows 64 bits, as its name suggests

I am aware that this change may break some code of your own, so please check if you are using IsWin64() and remember that it has to be changed to IsExe64() from FWH 13.07 on, thanks