centralize and fixup example sources install targets

This follows suit with aeb036e in qtbase.

Change-Id: Ie8580d0a1f38ab9858b0e44c9f99bdc552a1752a
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: hjk <qthjk@ovi.com>

examples/multimedia/spectrum/TODO.txt

@@ -0,0 +1,34 @@
+TODO list for spectrum analyser
+===============================
+
+Bug fixes
+---------
+
+
+New features
+------------
+
+* Wrap user-visible strings in tr()
+
+* Allow user to set frequency range
+There should be some constraints on this, e.g.
+  - Maximum frequency must not be greater than Nyquist frequency
+  - Range is divisible by number of bars?
+
+* Add more visualizers other than bar spectrogram
+e.g. Funky OpenGL visualizers, particle effects etc
+
+
+Non-functional stuff
+--------------------
+
+* Improve robustness of QComboBox -> enum mapping
+At the moment, SettingsDialog relies on casting the combobox item index directly to the enumerated type.  This is clearly a bit fragile...
+
+* For functions which take or return qint64 values, make a clear distinction between duration (microseconds) and length (bytes).
+A sensible convention would be that the default is bytes - i.e. microseconds must be indicated by adding a Us suffix, where not already obvious from the function name.
+
+
+
+
+