explicitly check if reference annotation and bigwig files match

[cnluzon]

It would be useful that this is checked beforehand.

summary_heatmap crashes when BED and BigWig file have different references, which is the right behavior, but the way it crashes does not hint that that is the cause.

[cnluzon]

Additionally generates an obscure problem in bw_bins analysis, with lots of failed to summarize range warnings for regions that look valid.

Sometimes we get those for some extra references, my guess is that these were not in the reference we mapped, one of those chr1_KN196474v1_fix sequences.