* Update files in src/plugins

Change-Id: Ia5d77fad7d19d4bb3498e78661982f68729adb22
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>

We have to make sure that all the nodes get deleted when the states are
deleted. Previously, we relied on the RenderState destructor to
recursively delete nodes owned by their parents. This is rather hard to
understand and can easily fail if we create a pass state without calling
TimelineRenderState::assembleNodeTree() afterwards.

The best way to deal with this is to properly encapsulate the nodes into
the states and add destructors which delete them.

Change-Id: I8b1ce16084afc1c85a90609f8f8d889147f7832f
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>

Change-Id: Id6fde7279f80cdc7a74322bcee4e0ce41f7fc3bc
Reviewed-by: Ulf Hermann <ulf.hermann@theqtcompany.com>

Change-Id: I964b2f149e237eb25a08600e8dab8968e8bc0cb9
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>

Change-Id: Ib5c0ec44bac213f544dfce533299bee03213b374
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>

Like that we can easily add different renderers to use the same render
passes, e.g. for the overview.

Change-Id: Ib7dcb77a45e74488971011310f53f7639286768d
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>

Like that we don't have to expose any private members and we don't have
to care about QSGNodes we'll never create in a render pass.

Change-Id: I4e71da24c85de8f8f73d58fc2e76dc5e82ee31ae
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>

The new namespace "Timeline" is for classes that are supposed to go to
the generic timeline library later.

Change-Id: I1f6dce59de2c37398b1ed89473e1a94ec020104b
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>

By using the scene graph we can retain the geometry for events in
the timeline on the GPU and potentially speed up the rendering for
large amounts of items.

Change-Id: I2cfbb8ef4ebc7b56f1977ec1facb4f2e7f2002ee
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>