Visual C++ Builds: Use Custom Build Rules

Use custom build rules in the Visual C++ projects because this enables
that the generated files get automatically regenerated when the associated
source files change and that the generated files can be automatically
removed when "clean" is requested.

Also drop some unneeded items from the property sheets.
Added Aragonese translation
Added Aragonese to po/LINGUAS
docs: improve documentation for AtkObject::children-changed signal

https://bugzilla.gnome.org/show_bug.cgi?id=684667
l10n: Update Japanese translation
Release 2.10.0
role: new role ATK_ROLE_TITLE_BAR

https://bugzilla.gnome.org/show_bug.cgi?id=709351
role: new role ATK_ROLE_BLOCK_QUOTE

https://bugzilla.gnome.org/show_bug.cgi?id=710463