Set missed fields in ParamBaseTranscode

Previously, these fields kept whatever value was set by
FillDefault. The corresponding fields were set properly within
sSpatialLayers, but the fields within the main struct were left
with the default values.

This doesn't change the hashes in the unit test, since these
fields don't seem to be used in the produced bitstream at all.
Respect the loop filter disabling encoder parameter

Previously the loop filter was unconditionally enabled
regardless of what encoder parameter was set. If using
SEncParamBase instead, the loop filter was always disabled.
Respect the iDLayerQp parameter in SEncParamExt

Previously the value set in the parameter struct was ignored
completely.
Merge pull request #338 from mstorsjo/use-encoder-params

Actually use the parameters set in SEncParamBase/SEncParamExt