[PATCH] Improved error output for qdbusxml2cpp

I did: qdbusxml2cpp org.kde.KdedGlobalAccel.xml -p test
and it said:

Got unknown type `ai'
You should add <annotation name="com.trolltech.QtDBus.QtTypeName.In1" value="<type>"/> to the XML description

That wasn't helpful though, because it didn't say in which method the problem was.
(many methods and signals use "ai" in that file)

And in fact, the second line was wrong too, since it was the Out parameter of a signal which
was missing the annotation. writeArgList() is called with the signal params into "inputArgs",
so "In" is wrong. I could have added yet another parameter, but I think it's cleaner to have
a writeSignalArgList with a single Arguments parameter.

=> The attached patch improves the error output to:

Got unknown type `ai' in `yourShortcutGotChanged'
You should add <annotation name="com.trolltech.QtDBus.QtTypeName.Out1" value="<type>"/> to the XML description

Testcase:
<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN" "http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
<node>
<interface name="org.kde.KdedGlobalAccel">
<signal name="yourShortcutGotChanged">
<arg name="action" type="as" direction="out"/>
<arg name="newShortcut" type="ai" direction="out"/>
<annotation name="com.trolltech.QtDBus.QtTypeName.Out0" value="QList<int>"/>
</signal>
</interface>
</node>

The bug is Out0 instead of Out1, that's a qdbuscpp2xml bug which I'll report+fix in a separate email.