Error message cleanup

[wes-b]

Fixes #567
Fixes #496
Fixes #302

Description of the changes:

• For access denied errors, where the device was already opened, I added additional logging to trigger the user to think about what might be cause the device to be unavailable.
• The use of LIBUSB now disables logging when calling libusb_open and libusb_get_device_list as both those API's return errors that can't be disabled.
• Rename 'queue_error' to 'queue_stop' as it is a better captures the state transition and allows de-escalation of error messages.

Errors and Warnings now seen when starting up K4aViewer:

[ warning  ] : depth_engine_thread(). Depth image processing is too slow at 76ms (this may be transient).
[ warning  ] : depth_engine_thread(). Dropping depth image due to bad timestamp at startup

Before submitting a Pull Request:

• I reviewed CONTRIBUTING.md
• I built my changes locally
• I ran the unit tests
• I ran the functional tests with a device
• I ran the performance tests with a device

I tested changes on:

• Windows
• Linux

[schultetwin1]

This is an awesome change. Thank you @wes-b!

[rabbitdaxi]