* Remove FormWidgetSignature::setFormSignatureType, the API was weird,
make it be an output parameter of getCheckedSignature

 * include cleanup

 * Make validation time mandatory, marking to use -1 for *now*

 * Remove setFormSignatureType noone uses

 * Fix compilation wihtout NSS3

 * Don't static cast between NSS3 HASH_HashType and poppler-qt5 HashAlgorithm

 * Actually pass validationTime down in FormFieldSignature::validate

 * Add since markers to poppler-qt5 functions/enums

 * Fix spacing

 * Remove SignatureValidationInfo::signingDateTime that returns
QDateTime, having two functions that return the same is a bit confusing,
and we're not filling the timezone info anyway, so let it be a time_t