Verbose definition of energy:values in RegularTimeSeries type

Created by: 900k

While writing an updated sample file for v0.5 I find it superfluous to have an opening and closing tag for each value of a time series. For 12 monthly values you will end up with this ...

<energy:values>
    66.5
</energy:values>
<energy:values>
    66.5
</energy:values>
<energy:values>
    39.9
</energy:values>
...
<energy:values>
    66.5
</energy:values>

I suggest to define the values element in such a way so that instances of it look like this ...

<energy:values>
    66.5 66.5 39.9 26.6 26.6 13.3 13.3 26.6 26.6 39.9 66.5 66.5
</energy:values>