Merge the allow_markup and plain_text settings into a single setting.
These 2 settings had a similar function, allow_markup controlled whether
markup was parsed or stripped and plain_text whether the notification
was escaped and displayed as is.
To cover all the possible combinations of the settings mentioned above
`markup` can take the following values:
full: The equivalent of allow_markup yes, plain_text no.
Passes the text straight to pango with minimal parsing. All valid
pango tags will be parsed.
strip: The equivalent of allow_markup no, plain_text no.
Strips the markup using string_strip_delimited. The parsing is
simplistic and if there are any unescaped '<' and/or '>'
characters it might get tripped and strip out actual text.
According to the GNOME notification specification, if a server
doesn't support markup(and we don't advertise that we do if it is
turned off) it should be stripped clientside, so this setting
should rarely be used. It is mainly left in for compatibility
with broken clients that don't follow the specification.
no: The equivalent of allow_markup [yes/no](any value), plain_text
yes.
Makes the notification content be rendered as plain text
regardless if it contains markup. Any Markup will be shown as
regular text.
Markup inside 'format' will still be parsed regardless of what markup is
set to.
Closes#279
notification_create currently simply allocates memory and zeroes it to
properly initialise a notification. Since we currently have at least 2
places in the code that create notifications(startup notification in
dunst.c and notifications from dbus in dbus.c) the creation should be
handled from a central location in case we ever need to change the
creation procedure later on.
