EMI: Implement head tracking.
EMI: Implement head limits.
EMI: Fixed Actor::getWorldPosition calculating the world transform incorrectly for attached actors.
EMI: Continuously update the look at vector when looking at an actor.
Merge pull request #947 from Akz-/emi-head-rebase2

EMI: Implement head tracking
GRIM: Set shadow userdata to nullptr when done with it.
GRIM: Implement a dim shader
GRIM: Implement GfxOpenGLS::dimRegion
Merge pull request #957 from klusark/dim

GRIM: Implement a dim shader
GRIM: Fix the dim shader compilation on android
ALL: ignore patch files in root directory of source
JANITORIAL: formatting headers
EMI: Fix inventory item rotation by correcting the Euler Order.
EMI: Fix trying to use the dim shader when it's not needed for EMI
SDL: Render the overlay when using OpenGL with shaders
SDL: Extract overlay rendering to different methods
GRIM: Rename createModel to createMesh
GRIM: Implement destroyMesh [OpenGLS]
GRIM: Fix destroyTextObject [OpenGLS]
GRIM: Initialize and delete shader programs [OpenGLS]