* Fixes issue 181.
* Refactors add_hello and adds unit tests.
* Adds endian to the list of dependencies
* Make the library modular usable.
* Some fixes in the article about the costs of async abstractions [skip ci]
* Switch to library requirements instead of source. As source puts extra source in install targets.
* Add missing import-search for cconfig/predef checks.
* Add requires-b2 check to top-level build file.
* Bump B2 require to 5.2
* Move inter-lib dependencies to a project variable and into the build targets.
* Update build deps.
* Fix spurious semi-colon.
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Co-authored-by: Marcelo Zimbres <mzimbres@gmail.com>