Spectator camera modes

[assertivist]

Allow spectators to switch to a 3rd person follow cam or a freely-movable static camera.

[Ymihere03]

PRs #391 and #392 have added a free flight camera used in spectator mode. A new file CFreeCam.cpp was added to contain all the handling for the new camera. Additional code was added outside the new class to make the new camera view get used at the proper time.

Here are the features that align with this issue:
Free camera can toggle on/off during spectator mode.
When toggled on:

• Free camera can strafe in the six orthogonal directions in 3d space
• Camera can rotate in a complete sphere around the sphere's center (camera always looks at the center)
• Camera can zoom in and out (changes radius of the sphere)
• User can select a player to follow using the existing Spectate Next/Previous controls
• Camera sphere will stay centered on the selected spectate player until the following occurs:
  • Free cam is toggled off
  • Spectate Next/Previous controls are pressed again
  • The camera is moved in any of the 6 orthogonal directions. Zooming or rotating the camera will keep the camera centered on the spectate player.
• At the time of this comment, HECTOR's are the only in-game object that the free camera can center on