Add identity _fullInput refs to fullTrace

[etpinard]

... so that gd._fullData[i]._fullInput and gd._fullData[i]._expandedTrace are always defined, that is, inside transform traces and non-transforms traces.

This, I believe, will make @VeraZab's live a lot easier for building UI buttons for ohlc and candlestick traces.

@bpostlethwaite can you think of a potential problem here?

[bpostlethwaite]

So code that only needs to operate on expanded transform traces can do something like self !== self.expandedTrace? I don't know if any of that type of code is in existence though. Not in fits or average yet anyway.

[etpinard]

@bpostlethwaite more like:

For example, ohlc trace type, traces in gd.data have type: 'ohlc' and OHLC attributes whereas traces in gd._fullData have type: 'scatter' and scatter attributes. When someone is looking for user-data + defaults (e.g. someone building UI buttons), that person needs to dig into gd._fullData[i]._fullInput - which was previously only defined for transformed traces.

[VeraZab]

The more I dig into our style panel specs, the more I realize that it would indeed really help.

[VeraZab]

💃