EMI: Fix inventory item rotation by correcting the Euler Order.
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]
GRIM: Implement destroyTexture [OpenGLS]
CONFIGURE: Properly check for GLEW when using OpenGL Shaders
TINYGL: fix typo in name
JANITORIAL: fix whitespaces
MATH: added few GLU helpers
GRIM/EMI/MYST3: drop usage for GLU functions for replacements
TINYGL: remove GLU leftovers
Merge pull request #958 from JoseJX/FixInventory

EMI: Fix inventory item rotation by correcting the Euler Order.
MYST3: Implement two sound opcodes
GRIM: Add override to a few missed classes
MATH: Make Matrix4::inverse not const as it changes data
MATH: no need do cast anymore in Matrix4::inverse
MYST3: Fix room background scripts not being run