Rename functions -> core, put widely use functions in helpers.rs

2 jobs for cleanup in 5 minutes and 56 seconds (queued for 1 second)
Status Name Job ID Coverage
  Test
failed clippy #563

00:03:38

passed test #562

00:02:18

 
Name Stage Failure
failed
clippy Test

error: aborting due to previous error

error: Could not compile `medal`.

To learn more, run the command again with --verbose.
Makefile:14: recipe for target 'clippy' failed
make: *** [clippy] Error 101
ERROR: Job failed: exit code 1