Adding Support for LSF 9

Resolves #21.

The APEL LSF parser doesn't currently support version 9. It currently only accepts version numbers 5 to 8.

According to Platform, new version logs should always be parseable by code written for older versions so the simple change to allow that version number should be sufficient.

Changes include:

- Add example log for LSF 9.
- Refactor code in line with refactoring of PBS and SLURM parser tests.
- Change invalid version test to use 10 instead of 9.
- Rename mapping_lsf_5678 to just mapping_lsf as support for 9 has been
  added and there are quite a few numbers now.
- Change instances of `assert` used to test negative values to `if...raise` (as per earlier PBS and SLURM changes) and add check for stop time less than start time.