Results 4 issues of Ashley Arthur

This change is as small as I can make it, so I'll try and break it down ### 1. CLI options to choose the source of screen capture source, device...

This is a simple implementation: - Checks pixel scaling via NSScreen bindings once at startup - it doesn't currently react to changing displays I'm not aware if this functionality is...

This PR is dependant on https://github.com/bitwhip/bitwhip/pull/11, see the second commit for the specific changes - I've created an iterator interface over an encoder + source to help structure the code...

On certain display sizes, anytime the stride length included some padding, av_image_copy_to_buffer would crash because it seems `create_texture_streaming` isn't including the padding in ITS buffer, so we write past the...