StrCoreAlloc* and StrAlloc*Secure

Rename the StrAllocate* functions to StrCoreAlloc* to make it easier to tell them apart from the original StrAlloc* methods.

Add the StrAlloc*Secure methods back as wrappers around the StrCoreAlloc* functions.
Because I think that

    hr = StrCoreAllocConcat(&sczFormat, wzRead, 0, !fObfuscateHiddenVariables);

is much better than

    if (fObfuscateHiddenVariables)
    {
        hr = StrAllocConcat(&sczFormat, wzRead, 0);
    }
    else
    {
        hr = StrAllocConcatSecure(&sczFormat, wzRead, 0);
    }