Given there is some async wibox redraw operations, there is a tiny,
tiny chance the test suite callback will be executed before the
redraw. It has been seen on the CI, so it is not 100% impossible.
* Move table functions out of awful.util into new gears.table
* travis: Use v9999 prefix for full requests
Make sure no newly deprecated functions are used
* Move all `awful.util.table.*` calls to `gears.table.*` calls
Move table test functions from awful/util_spec to new gears/table_spec
Change awful.util.subsets call to gears.math.subsets in awful/key.lua