Added option to load a TPM key from an UUID (untested)
Added the option to register a key
Allow importing a public key from UUID
Added functions to handle TPM stored keys.

Not everything is on working state.
internal functions marked as static
small fixes in TPM support
pubkey option can now accept a url
documented updates
Added support for legacy key
Allow tpmkey: urls in set_key_file()
do not list parent in URL.
doc fix
Added gnutls_pkcs11_advset_pin_function and gnutls_pkcs11_advset_token_function
corrected function call
Added ability to request PIN from a TPM URL. It uses the PKCS11 PIN function.
Added flag to disable the use of callbacks in TPM keys.
Allow gnutls-cli to be used with tpmkey urls
When verifying a certificate chain make sure it is chain.

If the chain is interrupted (wrong) at some point then truncate,
only try to verify the correct part. Patch by David Woodhouse.
Added functions that import any kind of URL into abstract public and private keys.

Added:
 gnutls_pubkey_import_url()
 gnutls_privkey_import_url()
Enabled the generation of signing keys.