Refs #7178. Add a test for existing log properties.

Though http://www.mantidproject.org/Run#ISIS_Muon_data does have
a list of run properties read from the Muon files, it wasn't checked
in any of tests before.
Refs #7178. Update test to check for new properties.
Refs #7178. Improve test robustness against type mismatch.
Refs #7178. Make names of new parameters better.
Refs #7178. Add code to read new properties from Nexus file.
Merge branch 'feature/7178_muon_temp_and_field_logs' into develop