move the "turn changed" alert code to mp_ui_alerts namespace
add { } to BOOST_FOREACH
create "turn_changed" preference under mp alerts
fix use of ...A( winapi functions for fonts.
remove "desktop notifications" adv. preference

We move the tooltips to the "mp_alerts_options" window which has
subsumed this preference.
fix tablature in data/gui/.../mp_alerts_options.cfg
update changelog
Merge branch 'more_notificiations'
update RELEASE_NOTES
update RELEASE_NOTES
move clipboard code to desktop folder and namespace
add desktop::clipboard::available function

So gui elements can determine if we actually have clipboard
support compiled in.
add left click handler to labels
add to font::ttext an interface to pango fcn xy_to_index

This is used implicitly in the "get_column_line" function but
sometimes you just want the index, for instance, if you want to
resolve whether a link was clicked on.
get text index for a text label when it is clicked on
replace "get_string_index" with "get_token"

The get_token function, for a font::ttext, takes a coordinate
position and a list of delimiter characters, and returns the token
pointed to, if the position is in bounds, and the character being
pointed at is not itself a delimiter. Otherwise it returns the
empty string.

We also add some debugging output to the label click handler,
so that on log channel gui/event, we can see example tokens and
whether they look like URLs.
add support to open clicked links, after prompting user

If the user clicks on a token in a gui2 label that looks like a
link, prompt them if they want to open it.
add "link awareness" to font::ttext objects

If link awareness is enabled, then tokens that look like links
will be rendered thusly, and a "get_link" function is provided
to check if a layout location is pointing to a token which was
rendered as a link.
link-aware rendering of labels

This commit adds a new property of font::ttext, whether it is
"link aware". Link aware text has tokens that look like hyperlinks
formatted thusly, with coloration and an underline.

A `get_link` function, taking a layout location, returns a link
token if it is pointed to at that location, and link awareness
is enabled, and the empty string otherwise.

All gui2::tcontrols may now have their text labels set to be link
aware if desired. The gui2::tlabel constructor automatically sets
these to be link aware. The gui2::tlabel click handler is set to
use the `get_link` function instead of the `get_token` function.

Link awareness is also registered as a property of [text] fields in
gui widget definitions.
if opening links is not supported, tell the user so when they try