By reducing bit-depth of audio, quantization noise is introduced. If the
bit depth is reduced by consistent rounding (either always down, always
up, or always to nearest) the quantization noise is correlated with the
input signal and percieved as distortion. Adding a small amount of noise
to the input signal before reducing the bit-depth causes random
rounding, which makes the noise uncorrelated and uniformly spread
through the whole spectrum.

NDI is already handled separately.

Do not group "free" SDKs - XIMEA was only one, anyway, NDI handled separately.

This allows having some formatting in FIXES.md, eg. for different minor
versions like that:

    #### 1.7.1
    - changes for 1.7.1
    - another fix in 1.7.1
    ### 1.7.2
    - fixes for 1.7.2

+ join the lines like beginning with spaces more inteligently

and build it unconditionaly.

Allows compile time -DUSE_NDI_VERSION override.

- added C guard to inclusion of stdbool.h in host.h
- misc.h - added MERGE macro - MERGE_ is already defined in host but
  this is for a general use, the MERGE_ is left in the host.h not to
  introduce additional dependency

+ warn if capturing 16-bit YCbCr

Removed separate NDI handling (branch ndi-build and build it as upstream (if SDK is found)
since NDI is now dynamically runtime loaded.

To avoid adding NDI library yet allowing user to install it separately and use it with UG.

Coverity doesn't provide ETag but a filename with content-disposition
header, eg.:

    content-disposition: attachment; filename="cov-analysis-linux64-2020.09.tar.gz"

- lavc in summary not yet in right row but better

- removed tab from help
- code doc
- fixed an assert

detects only drops longer than 1s

Previously it was possible to only use size - 1B, because filling the
whole buffer would make start and end indices equal, making the buffer
appear empty. This is important if we want to allow direct zero-copy
access to the buffer while storing multi-byte elements.