.config/awesome: custom/util.lua: fix file resource leak in read_file().
.config/awesome: rc.lua: improve terminal handling, make ontop terminal kludge-less.
.config/awesome: rc.lua: add systray to the first screen only.
.config/awesome: rc.lua: refactor client handlers; center floating windows.
.config/awesome: rc.lua: minor refactor.
.config/awesome: rc.lua: add rules for Inkscape and LibreOffice.