Composite balloons, step 1: simple newly-allocated text component

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>
Copyright notices

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>
Use object pool for TextContentViews

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>
Support for image content view (composite balloon)

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>
Fix possible exception while moving layout children

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>
Merge branch 'composite_balloon' into audio_message