Prepare documentation for 6.0 release.
The purpose of this issue is to make sure that documentation for the final release (6.0) is usable by the end user. Right now, only dry API documented. We need to incorporate the existing text to the new format and adjust accordingly. I thin that autotools should be shipped as a main build system for the new release. The meson has a bug and documentation can't be generated by the end user. However, meson should be sync with autotools as much as possible and eventually completely migrated when all components can be built.
Edited by Pavlo Solntsev