Feature angular ui

DO NOT MERGE - for discussion only
I am really concerned in this project with data integrity, as mentioned in https://github.com/fritzo/puddle/blob/master/doc/contributing.md The data puddle is concerned with is exactly this corpus, which is a precious codebase. Moving to mongodb for server-fault-proof persistance is good. But the master copy of the corpus should still be kept in git in a human-readable human-editable form.