API Break: correct namespacing and make WeatherInfo more GObject friendly

This also re-implments libmateweather's gsettings code that was closely
tied to the api changes.

WeatherInfo becomes MateWeatherInfo, a GObject, with private data (it
was already opaque), properties (write only for now, I plan to improve
on that later, when I'll convert all getters) and signals. WeatherLocation
has been removed, you can now either pass a MateWeatherLocation (obtained from
the database), or use the default from preferences. WeatherPrefs was
removed.

Taken from libgweather commits:
  0729a784672e2a26fe19185c01562798039eb926
  7d32d907d0997d8dbdafc08ca807f132820660e3

From: Giovanni Campagna <gcampagna@src.gnome.org>
Weather: move weather.h to gweather-weather.h

Public headers should have a namespaced name, and should also be
installed.

Taken from libgweather commit: c92d71b772c23b8dcdaf1e5baea8a1bba890c4da
From: Giovanni Campagna <gcampagna@src.gnome.org>
GWeatherXML: use meaningful column types in the tree model

Now that WeatherLocation is no longer a public type, we should avoid
using it in public places like the mateweather-xml tree store.

Taken from libgweather commit: 1e11b351c0c278059b0bc7ce4929056d542826aa
From: Giovanni Campagna <gcampagna@src.gnome.org>
MateWeatherInfo: clean up functions returning strings

Instead of using static buffers inside the functions, allocate new
memory and make them (transfer full). This should help with reentrancy
and thread safety.

Taken from libgweather commit: ca62c0cf78f2cd749a47c75abd853124bbd0dbc7
From: Giovanni Campagna <gcampagna@src.gnome.org>
docs: lots of small fixes

 * add deprecation guard to mateweather_location_free_children
 * remove overrides
 * update sections for current code
 * Fix some annotation
build: intltool 0.50 properly support gsetting schemas
gtk-doc: Add section and missing sections
libmateweather-docs.sgml: remove weather.xml
Makefile.am: Use AM_DISTCHECK_CONFIGURE_FLAGS

The DISTCHECK_CONFIGURE_FLAGS variable should now be reserved for the
user.

http://lists.gnu.org/archive/html/info-gnu/2011-12/msg00008.html
MateWeatherConditions: fix bindings

Apparently, g-ir-scanner needs to see the typedef before the
structure, or it fails to resolve the type

Taken from libgweather commit: 4692215fd2a726355d7b52c5f8b82d7ea0d99fd1
From: Giovanni Campagna <gcampagna@src.gnome.org>
Associate the metar code cache with a specific world

MateWeatherLocation are strongly associated with the world node that was
created when the database was parsed, and they become useless when
disconnected. This way, the API user can keep a world node alive
and ensure that all locations are from the same parser run.

Taken from libgweather commit: 1800633598f1cbe1af09716d5bdbcdc6f7711665
From: Giovanni Campagna <gcampagna@src.gnome.org>
LocationEntry: use boxed for MateWeatherLocation

MateWeatherLocation has been a boxed for quite a while, update the
property registration code to match that.

Taken from libgweather commit: 580736b962611bfa87b922a936274711688a7556
From: Giovanni Campagna <gcampagna@src.gnome.org>
Add gweather_info_new_for_world()

A constructor to be used from C, that allows to control the world
property and thus the hierarchy to which location belongs.

Taken from libgweather commit: 7f23e24ae389b23a875c1475db3e7c918b87b2e7
From: Giovanni Campagna <gcampagna@src.gnome.org>
Use locale insensitive g_ascii_dtostr() when building URI

g_strdup_printf() depends on locale for %f, so using it results
in URIs that fail because coordinates have commas instead of
periods.

taken from libgweather commit: 2e34b2a04d1123d44d606f5d58b56372972aee59
From: Giovanni Campagna <gcampagna@src.gnome.org>
Ensure that only public API is visible from outside

Every visible symbol must be properly namespaced or it will cause
conflicts. Instead of renaming everything to start with _gweather,
use libtool's export-symbol-regex to create a filter.
Also, create a new static library that is used for tests, and apply
the filter only to the installed library.

Taken from libgweather commit: 5675f069520ef5dcf99499c4324f0879042a9ad3
From: Giovanni Campagna <gcampagna@src.gnome.org>
iwin: actually queue the request for forecast-list

The previous fix for %f formatting removed too much code, including
that queuing the HTTP request.

Taken from libgweather commit: 73d9b7fcd3801c0d1634c15520fe3a85d370c8dc
From: Giovanni Campagna <gcampagna@src.gnome.org>
Sync Locations.xml.in with libgweather commit: d31d486eba89b39959a32ef2bc0ded588c455b26

This is the update (~2012-08) before yahoo is added as provider.
test_sun_moon.c: Fix warning
Add Yahoo! Weather forecast provider.

Adds a forecast provider that uses Yahoo! Weather RSS channels to
retrieve informations. For the time being, this requires a new tag
in the database, <yahoo-woeid>, containing a Where on Earth ID (the
one for Milan is provided for testing purposes).
The matchings from Yahoo condition codes to MateWeatherConditions and
MateWeatherSky need to be checked.

Taken from libgweather commit: 349f453c9ac8c8b464b631b6c53e1de30932bc77
From: Giovanni Campagna <gcampagna@src.gnome.org>
Add support for hidden intermediate administrative divisions

yr.no wants to see the district/region name at all times, but we don't
want to show them in the location entry. Let's put ADM2 to good use for
this

Taken from libgweather commit: 79a6010d4fd45537c6daacbd26b7aa67427080e7
From: Giovanni Campagna <gcampagna@src.gnome.org>