Searching in a huge mail box is buggy and takes a long time. The reason is that after each typed character a new search starts. * [x] ~~Add a timer such that a search query is send only after a couple of milisecs with no input.~~ there's now a configurable delay in `InboxViewController` before the search is executed * [x] ~~Can you improve body search queries ?~~ see update * [x] possibly refactor search in `InboxViewController` **UPDATE 26.02**: the search now looks for the separate terms in a scrambled order as well. A strict order can be enforced if the search is wrapped in "". So `car box` looks for either of the two words in whatever order, `"car box"` matches the whole string