k_qsvs todos

[lcolladotor]

• Similar to #9
• Import num.sv https://github.com/LieberInstitute/DeDHed/blob/53103928435e2fdade736de338d52bb08cc3ec36/R/k_qsvs.R#L11.
• Use the assayname argument like at #10.
• Check that the mod_tx object is a matrix (or model.matrix output).
• If it has to be a full rank model matrix, then consider adding something like https://github.com/LieberInstitute/jaffelab/blob/master/R/cleaningY.R#L83. This code comes from https://github.com/lcolladotor/derfinder/blob/e9a7ef2c79fd22167ff2bb176a95b75582341163/R/makeModels.R#L110. Double check if we need to import the qr() function.
• Are we using the +1 here like at #10? Maybe they should be consistent.

[joshstolz]

updated with all recommendations above. I don't believe we need qr() (maybe ask leo for advice here)