Azimuth sign flip between target spawn and player aim

[bboudaoud-nv]

It seems that the azimuth value reported in the spawn_ecc_h in the Targets table has the opposite sign from the azimuth value reported in the Player_Action table's position_az column. We should investigate this math and make sure the two azimuths are computed the same way.

[bboudaoud-nv]

This issue has some added complexity that likely needs to be addressed. Notably:

• The player aim direction is reported directly from the camera->frame()->lookVector() (no initial heading adjustment)
• Target spawn eccentricity is reported before initial heading adjustment, but modified afterwards for actual spawn
• The target spawn direction azimuth doesn't follow the same convention as the view direction (right positive vs right negative)
• The scene spawnHeading doesn't seem to be used anywhere, but is documented as though it modifies the initial heading
• The Session::initialSpawnHeadingRadians variable is initialized from player->heading(), which comes directly from Any (I believe the scene.Any file)

At a high-level we should:

1. Adopt a consistent convention for reporting azimuth heading (I suggest positive for clockwise)
2. Enforce a uniform, documented way to set initial spawn heading (not clear what is best here) a. Perhaps we want to default to the scene file heading, but allow modification from the experiment config scene specification
3. Use the initial spawn heading consistently throughout control and reporting