Minor code cleanup

Minor code cleanup including:

1. display meaningful warning if lock file cannot be deleted
2. use faster method calls
3. remove unused method parameters

These changes can be viewed at https://gitlab.com/743zpnpGUq27GgR/exonerator/-/commits/small-cleanup

or cloned via

https://gitlab.com/743zpnpGUq27GgR/exonerator.git using branch 'small-cleanup'

Feel free to use whatever makes sense and ignore the rest. Thanks! Josh

Trac:
Username: efgyirfe784