fix error with unregistering worker and type conversion

[m-fila]

BEGINRELEASENOTES

• Fixed error with unregistering worker and invalid return type conversion

ENDRELEASENOTES

Added missing wait so the rmprocs task is finished before exit leaving the program in cleaner state. The task was also implicitly used as a return code of @main when using remote workers - now the implicitly returned values is nothing which results in 0 exit code from the program