Fixed NULL pointer dereferencing in linked lists
Merge pull request #271 from GoaLitiuM/master

Fixed NULL pointer dereferencing in linked lists
Ensure num_backbuffers > 0 in gs_swapchain_create
Do not modify gs_init_data parameter in gs_create
(API Change) Use const params where applicable

This Fixes a minor flaw with the API where data had to always be mutable
to be usable by the API.

Functions that do not modify the fundamental underlying data of a
structure should be marked as constant, both for safety and to signify
that the parameter is input only and will not be modified by the
function using it.
cmake: Properly check for Threading support
cmake: Refactor growing list of library locations
cmake: Replace FFMpeg modules with single module

Now using components instead of one find_package call per module
cmake: Change obs helper macros to functions
cmake: Add helper function to install plain files
cmake: Export plugin data destination
Use qt.conf instead of hardcoded, runpath dependend, lib path