repeater-thumbnail-justify: fixes #851 by coming up with an alternate justify solution

repeater-thumbnail-justify: fix to 'thumbnail_setSelectedItems' after making justify changes, which also makes unit tests pass

repeater-thumbnail-justify: yet another minor fix because lint yells about something dumb

repeater-thumbnail-justified: minor touchups after review

repeater-thumbnail-justified: additional function name improvements

repeater-thumbnail-justified: converted to thumbnail_alignment option instead so now center / justify / left / right (as well as 'none' or false) is supported

repeater-thumbnail-justified: added unit tests. also added "spacer" class to injected spans

repeater-thumbnail-justified: added default font-size for thumbnail