replace unlicensed icons/images:
 * fugue icons (http://p.yusukekamiyamane.com/) CC-BY-SA license
 * ornimental bookend (https://openclipart.org/detail/19869/ornimental-bookend---left-by-j4p4n) Public domain license
 * Paper_texture_v5_by_bashcorpo_w1000.jpg source found at http://bashcorpo.deviantart.com/art/Grungy-paper-texture-v-5-22966998 under Public Domain license
daily: icons: remove forced size on squiggle2 to display it properly
move copyright information from README.md to COPYING, add credits.
 * Fixes https://github.com/shaarli/Shaarli/issues/10
 * Fixes https://github.com/sebsauvage/Shaarli/issues/8