implementation ChromBackend

[philouail]

So there is still a lot lot to do but as discussed I am trying to reduce the size of the PR. I hope that does not make it too confusing.

The big changes are the clear separation between what is a peaksVariables and what is a chromvariables.
See ChromBackend-functions.R

Also implementation of respective function for each such as validPeaksData() and validChromData()

Quick question:

• I added a replacement method for chromIndex, is that okay or in general we don't want people to change that ?
• is it a problem that chromData() returns a data.frame and not DataFrame ? I don't really see the issue for now..

Next I will add the ChromBackendMemory() implementation, i have the code, just need to clean it.
Also will look into some maintainer stuff, if you have advices don't hesitate.

[philouail]

I changed the .yml file, the checks should not fail on warnings anymore :)

[jorainer]

Looks good Phili! Thanks! Just some minor change requests.

Regarding the question if chromData() should return a DataFrame or data.frame, I don't see a problem for data.frame at the moment - so, given that it is also slightly more efficient, I would maybe change to data.frame instead of DataFrame.

[philouail]

Hi so I answered / addressed the comments, thanks for the advices ! I went through the documentation a bit more realised I missed removing some stuff also.
tell me if there is something else :) and for moving the reset() to ProtGenerics also

[jorainer]

Looks good now, thanks Phili!

Before merging make sure you fix the two comments/issues in the documentation.

Regarding reset() - yes, we might want to add that to ProtGenerics, but for now define it also here. We can change later.