API to query samples by index sequence or index ID

[dshao]

Given a Index sequence or Index ID, return a list of sample IDs.

[dshao]

Also API to query samples by Genome Build.

[dshao]

add a feature on PEGR Samples page for searching samples by tag?

It's pretty often the clients ask me about HA, His, FLAG, Myc tags. Occasional V5. Right now I have to guess at what antibody we used in order to search, so this would be a great feature. His tags will usually say "6xHis", somethings "8xHis".