In `i3 4.16`, `i3-nagbar` introduces the flags `-B/--button-no-terminal`
to run the action directly instead of inside a terminal. This implements
the flags for swaynag for compatibility.
Since swaynag does not use an equivalent to `i3-sensible-terminal`, the
flags `-b/--button` only uses a terminal when the environment variable
`TERMINAL` is set, otherwise it acts the same as these new flags.
Fixes segfauls for any case where swaynag->outputs was not inititalized
including -h/--help, -v/--version, and invalid arguments.
Sets sane defaults for colors not given. Any color not given will
fallback to the default color values for type error.
Adds support for a hidpi cursor
