transMapPsl doesn't show base mismatches in browser

[diekhans]

This is because the query sequences has not been added to the bigPsl

also it would be good to to turn on these options by default:
Draw double horizontal lines when both genome and query have an insertion
Draw a vertical purple line for an insertion at the beginning or end of the query, orange for insertion in the middle of the query

[diekhans]

also, would be good to include source id information in transmap PSL

[diekhans]

for some reason, the query deletion lines don't show even when you turn them on. We need to investigate this. might be a browser bug.