* CORDA-876 MockNetwork no longer leaks serialization env if init fails (#2272)
* Removed all remaining special treatment of the X500 common name.
* Move unspecifiedCountry to internal. (#2274)
* Merge fixes, which includes fixing the doorman tests and updating the doorman to not set a CN in the CSR responses
* Redo legal name validation rules so that direction change chars are rejected
* Split name validation into minimal rules that all nodes can require, plus extended rules that the Doorman will apply (and we may need to change, without updating the entire network).
* Break down name validation rule sets to better match expectations
* Add test for nulls in Corda names