* Refactor serialized keys into own structure, in preparation for making Key an interface.
* Refactor key logic into separate structures for each platform/TPMversion invariant.
* Implement review feedback
* Generate and store a fake EK certificate in TPM 1.2 test setup.
* Fix run of gen_ekcert.go
* Write out NVRAM cert header when generating ek cert
* Remove build flag gating tpm12 tests.