Merge branch 'feature/remove_unused_functions' into 'develop'

Cleanup of directory structure and removed obsolete files and functions

See merge request !51
4 jobs for develop in 29 minutes and 44 seconds
Status Job ID Name Coverage
  Test
passed #8509
debian:10 clang-6-libcpp-17

00:29:44

passed #8508
debian:10 gcc-8-17

00:20:40

passed #8510
debian:9 gcc-6-14

00:22:30

passed #8511
ubuntu:18.04 clang-6-17

00:28:17