* Add missing headers so all header files compile independently
* Add github actions script to check if all headers compile independently
* Remove unused headers from algorithms (not detail) and core and fix headers in tests
* Fix typo in headers.yml and missing header in srs
Adaptions to test with respect to new namespace model
Removed GMP/CLN and, where it was present, replaced by TTMATH
Small fix in comparable_distance test
All testfiles use bg as alias now
[SVN r66811]
