Add a function to consolidate and tidy raw BCEA data tables

[stephhazlitt]

From discussion:

...consider some naming conventions for these type of functions. That way if/when those get spun off into a separate package, they still make sense. The verb_noun combo works well but I don't know if tidy quite fits? join_bcea? consolidate_bcea? merge_bcea? fuse_bcea? pool_bcea? integrate_bcea?