Error: relayout dialog
Settings: move related stuff to detail pref fragment

split detail-view related preferences from screen layout.
[1/2] Settings: add option to download full-size image
[2/2] PostDetail: respect download full-size pref
Picasso: properly adjust thread count

has to set both core pool size and maximum pool size for thread pool
executor to work properly.
SiteSession: tweak rating filter sql
SiteSession: allow unknown creation date

the creation date might be unknown for the first fetch, just ignore it
and fetch the first page.
PostDetail: code clean-up
TouchImageView: calc max scale based on crop scale

sometimes the image might be in some really weired aspect ratio, results
maxscale < cropscale.
for example very tall or very wide images (like 3000x100 or 100x3000).

calculate max scale based on crop scale, so we always get min <= crop <
max
TagSearch: disabling the item when id == -1

disables the item, some API doesn't have tag search, just stuff a fake,
disabled tag to indicate that we can't do that.
SiteAPI: add shimmie api

uses the danbooru client extension, no tag search.
SiteAPI: refactor GelbooruAPI