Fix language consistency in names and descriptions

[charphi]

When the prefered language is not specified, the library takes the first available.
Some sources do not order theirs languages in a consistent way whithin the same response.

For example: the command sdmx-dlx list flows ESTAT returns dataflows with different lang order.

<s:Dataflows>
	<s:Dataflow id="MED_PS112" urn="urn:sdmx:org.sdmx.infomodel.datastructure.Dataflow=ESTAT:MED_PS112(1.0)" agencyID="ESTAT" version="1.0" isFinal="false">
		<c:Name xml:lang="fr">Population au 1 Janvier, par sexe et groupe d'âge</c:Name>
		<c:Name xml:lang="en">Population on 1 January by sex and by age group</c:Name>
		<c:Name xml:lang="de">Bevölkerung am 1. Januar, nach Geschlecht und Altersgruppe</c:Name>
		<s:Structure>
			<Ref id="MED_PS112" version="10.0" agencyID="ESTAT" package="datastructure" class="DataStructure"/>
		</s:Structure>
	</s:Dataflow>
	<s:Dataflow id="MED_PS115" urn="urn:sdmx:org.sdmx.infomodel.datastructure.Dataflow=ESTAT:MED_PS115(1.0)" agencyID="ESTAT" version="1.0" isFinal="false">
		<c:Name xml:lang="de">Durchschnittliche Bevölkerungszahl zur Jahresmitte</c:Name>
		<c:Name xml:lang="en">Average population (mid-year)</c:Name>
		<c:Name xml:lang="fr">Population moyenne (en milieu de période)</c:Name>
		<s:Structure>
			<Ref id="MED_PS115" version="10.0" agencyID="ESTAT" package="datastructure" class="DataStructure"/>
		</s:Structure>
	</s:Dataflow>
        ...
</s:Dataflows>

[charphi]

Done in aec3c2b

[charphi]

Improved in 64d6c89