Minor bug fixes

Hello,

Found a couple of issues under Visual Studio 2012:

1) When constructing the lda object, the member sorted_features did not get properly initialized. This was because its constructor was not called; the lda object was allocated with calloc, not new, which is not good for the non-POD member sorted_features. As a result, the debug build complained when trying to sort the vector (or just comparing the vector's begin() to end()). Changed to using new instead. (First with placement new, then just plain new.)

2) In copy_audit_data, there appears to be a clear bug, which the VC compiler pointed out as dst was not even initialized.

Best regards,
Juha