bcMerge on a list

[SGMartin]

I propose to expand bcMerge so that it can merge a given bc object with a subsequent list of bc objs, like Seurat does.

[mj-jimenez]

Right now, you can merge beyondcell objects with different signatures generated with the same single-cell matrix. You can't add cells from another matrix because the BCS are normalized and scaled using all the cells in the matrix.

• One workaround right now would be to input a merged Seurat object to compute the BCS.

• In the future: we have a @data slot that is equal to @normalized. We could convert @data into a list with 2 matrices for the sumexpr "up"and "down". Then, in the bcMerge function we could renormalised all the raw scores using the sumexpr and the new mean and sd.