Creating a new module to consolidate animation related classes.

Creating a new module, vtkPVAnimation, to consolidate all classes
related to animation in ParaView into a single module. This makes the
core/rendering modules a little leaner.

Also fixed module dependencies by making several of them
private dependencies.

Change-Id: I9059875d2d37c979d3f7420e3966eb57594dfec9
BUG #14673: Fix follow data.

Follow-data bug arose becase the "reset-camera" would happen before the
scene had updated the views, which is where correct time is passed to
the view.

In order to fix follow-data, we needed to add structure to when cues get
added. To make that possible, we merged vtkPVAnimationScene and
vtkSMAnimationScene since the two don't need to be separate anymore and
cleaned up the "Tick" logic to add this order specific update of cues.

Currently, I am doing that based on the type of the cue. Eventually, we
can add support for "priorities" or something like that it make it more
extensible.

Change-Id: If5c77b43b7b1b56d78e279d6a25cf0f0d39500a8
Merge topic '14673_fix_follow_data' into next

1f31485e BUG #14673: Fix follow data.
db3dadb9 Creating a new module to consolidate animation related classes.
KW00001440: Fix plugin library unloading.

When running pvpython, if your Python script loaded some plugins (from
shared libraries) and called "quit" or "exit" in the Python script
itself, pvpython would segfault, if you created a proxy from the plugin.
The problem was arising from the fact that the plugin shared library was
unloaded before the VTK object corresponding to the proxy was destroyed
during ProcessModule singleton cleanup. This was happenining because the
vtkPVPluginLoader cleaner singleton (which unloads libraries) was
finalized before the vtkPVPluginLoader singleton (which cleans up
unreleased proxies).

Fixed by adding a Schwarz counter to ensure that the plugin loader is
not finalized before the process module. Since vtkPVPluginLoader.h is not
included in a large number of translation units (and there's never need
for it), the overhead for this is minimal.

Change-Id: I0db6f4fc4e0657a623cb2dccefbb55a90ec05cab
Merge topic 'fix_plugin_loading_order' into next

fcc67852 KW00001440: Fix plugin library unloading.