trust: Implement reloading of token data

trust: Implement reloading of token data

 * Reload token data whenever a new session is opened.
 * Only reload files/directories that have changed.
 * Move duplicate anchor/blacklist detection logic into
   the extract code. This is in line with the approach
   being discussed on the mailing lists and spec document.
 * New internal attribute CKA_X_ORIGIN set on all objects
   so we can track where an object came from, and replace
   it when reloaded.

In general this is a prerequisite for modification of objects
reload before modify is necessary to prevent multiple callers
clobbering each other's changes.