/*=========================================================================

   Library: iMSTK

   Copyright (c) Kitware, Inc. & Center for Modeling, Simulation,
   & Imaging in Medicine, Rensselaer Polytechnic Institute.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0.txt

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

=========================================================================*/

Sreekanth Arikatla authored Jan 31, 2017 and Alexis Girault committed Jan 31, 2017

Scene can be set as current in the simulation manager using the scene
pointer in addition to its name.

Co-authored by: Nicholas Milef <milefn@rpi.edu>

1) DeviceClient : not a module anymore, only stores device info
and holds callbacks

2) VRPNDeviceClient : subclasses DeviceClient AND Module, to
conserve the ability to run multiple clients in parallel with
a VRPN server

3) HDAPIDeviceServer : new module that manages the HDAPIDevice
clients execution, which need to be made sequentially. Also helps
managing a unique hdScheduler.

4) HDAPIDeviceClient : lets the HDAPIDeviceServer handle the
hdScheduler. Also makes use of hdMakeCurrentDevice.

5) SimulationManager : refactor to run modules instead of
deviceservers or deviceclients

6) Sandbox : use new simulationManager API to add modules

Style enforcement and add comments over the entire code

1) Only update the renderWindow in setRenderingMode if
the viewer is up and running

2) Do not set a renderMode when setting a new current
scene if the viewer is not yet rendering.

(1) `SimulationManager::startSimulation()` will check if a Viewer is
already rendering, and will only start a rendering/interaction loop
in the main thread if it isn't. This allows us to work with two
possible cases:
(a) a QT Application with an existing widget for rendering, in which
case we do not want to control the rendering window ourself in a loop
(b) a standalone `vtkRenderWindow` application, in which case we do
want to create a window when our simulation starts and loop until the
window is closed.

(2) `SimulationManager::startSimulation()` can be launched with a debug
boolean option (off by default), which will allow to not automatically
simulate the dynamics of the scene, to be able to interact with the
scene beforehand (using the mouse).

(3) `imstk::InteractorStyle` is based on vtkInteractorStyle specifically
the trackballCamera and allows to ignore mouse events in simulation mode,
and uses key events to control the simulation:
's' : start simulation
'e' : end simulation
' ' (space) : pause/run simulation

(4) The `Viewer` class and the `InteractorStyle` class have been moved
to the `SimulationManager` module, since they are more drivers of the
application themselves.

(5) The 'Sandbox' example has been refactored to make it easier to test
autonomous tests, and updated to use the new driver architecture brought
with this commit.

- SIMULATION adds the object actors and set the
interactor style to no interactions.
- DEBUG adds additional actors to visualize
lights, the camera, axis, and set the interactor
style to trackball to interact with the scene.

The scene needs to be paused, but not the viewer.

Can directly used to create visual objects.

Also use unordered_map in SimulationManager.

Use config based on https://gist.github.com/mkroman/1372117

Also remove headers in cmake files

Adding project name (iMSTK)

Skeleton of CMake architecture and of first few classes.