glib/tests/date.c: Fix the tests on non-English Windows

The names of the month (and abbreviations) are specific to the Windows
system locale, so we need to use SetThreadLocale() to set the locale of
the running program to en-US so that it will parse "March" and "Sept" etc.
correctly.

https://bugzilla.gnome.org/show_bug.cgi?id=719344
glib/tests/keyfile.c: Use g_close()

Use g_close() instead, as close() is really found in io.h on Windows, not
unistd.h as on Unix, and hence unistd.h is not universally available.

https://bugzilla.gnome.org/show_bug.cgi?id=719344
glib/tests: fix build
Document g_test_run() order better, and how it changed

But also note that the ordering is strictly an aesthetic/convenience
thing, and that tests should not be written to depend on it.

https://bugzilla.gnome.org/show_bug.cgi?id=721624
Add includes to all gio docs
gdbus: properly escape introspection annotations

Make sure we escape any special characters that are found in annotation
names or values to avoid emitting a malformed XML document in response
to an Introspect call.

https://bugzilla.gnome.org/show_bug.cgi?id=721796
gdbus-introspection test: test escaping attributes

Make sure attribute values are properly escaped in generated XML.

https://bugzilla.gnome.org/show_bug.cgi?id=721796