Add non-standard position convention.
Created by: mutalyzerbot
Original ticket: https://humgenprojects.lumc.nl/trac/mutalyzer/ticket/101 Original date: 2012/07/10 Original reporter: j DOT f DOT j DOT laros AND lumc DOT nl
In r563 we switched to the official positioning system as recommended by the HGVS. This means that the +d and -u positions are no longer available.
It would be nice to supply both, which means a lot of changes to the interfaces.