Fix MutableTimeseries shadowed by MutableScatterXY

[simchanu29]

I noticed on the last commit of the main branch I weren't able to use MutableTimeseries. It seemed after some investigations it was always overshadowed by MutableScatterXY.

Way to reproduce the bug :

1. Use Reactive Function Editor
2. Create a new MutableTimeseries
3. The created timeserie is a scatter plot.

I guessed it was because new_usertype in sol overwrite last type if a previous type with a different name but same base class has already been declared. So I used inheritance to declare two subtypes CreatedSeriesTime and CreatedSeriesXY deriving from CreatedSeriesBase.

Side note I also added lua math that I think was missing.

[facontidavide]

thanks a lot. I should release this fix soon