Resolve "segmentation fault in unit-test Field.PeriodicBC"
This MR:
- Resets output stream in PeriodicBC. This fixes an occassional segfault when running multiple tests after each other (closes #570 (closed)) (a299a45f)
- Fixes memory errors in unit tests as reported by valgrind: initialise array, check for container end, array deletion (eeda59a1)
- Adds license header and cleans up whitespace for the affected IPPL files (ca98271d)