1 * implement RFC 4685 (Atom message threading)
2 * configurable constants (quote folding, index limits)
3 * use tags as date-based skiplists for navigating history
4 * improve + document mlmmj integration, currently only at:
5 http://bogomips.org/unicorn-public/20140508084301.GA2033%40dcvr.yhbt.net/