Perspectives server v3.0 and v3.1

Hey Dan! I made some changes to the sever code ;) Here is the high-level overview (also inside CHANGELOG). Let me know what you think!


v3.0
--
+ Separate the database interface from the notary code.
    This lets us change the type of database much more easily,
    and gives us a central way to organize other modules that communicate with the database.
+ Use SQLAlchemy as a database ORM, to make database abstraction and maintenance even easier (and cleaner).
+ Refactor database tables to be 3rd Normal Form.
* Explicitly add a Primary Key of (service_id, key) for Observations.
	This was semi-implied before, as keys could not be null, and it doesn't make sense to have a null service_id.
	SQLAlchemy requires tables to have a Primary Key anyway.
* Fix bug when reporting observations that would attempt to update the previous key's end time when there was no previous key.
	(this was harmless, but saves us running an extra query that returns no results)
+ Clearly separate utility scripts and modules that do *not* rely on the notary database (in 'utils/') from those that do (in 'notary_utils/').
+ Separate client modules into client/
* Refactor standalone modules so they can be run by themselves or when imported by another module.
    Database functionality was removed from modules in util/ so they comply with the "Do One Thing Well" philosophy.
+ Implement clean argument parsing for all modules using argparse.
+ Add documentation and docstrings to many things that needed it
+ Explain the tasks a network notary server performs in the README
+ Add default arguments and actions wherever possible, to make it easier to set up and run a network notary server without having to read (or understand ;) anything.
+ Add --write-config-file and --read-config-file switches so all modules that connect to the database can share settings more easily.
+ Add a static index page to explain what a 'network notary' server is to visitors.
+ Add AUTHORS and CHANGELOG files



v3.1
--
+ Add support for caching of service data with memcached, memcachier, or redis, to reduce database load.
+ Add metrics tables to allow tracking of useful performance statistics. See doc/metrics.txt for a detailed explanation.
+ Display whether a notary tracks performance metrics on the static index page
+ Add --dburl switch so db connection info can be easily passed all at once
* Fix bug where the notary server would use too many database connections (it now properly closes sessions and connections).
+ Attempt to fail gracefully in the face of catastrophic database errors
	- Attempt to fall back to the cache if we can't get data from the database
	(e.g. if there are too many connections or something went terribly wrong)
	- Fall back to printing and then ignoring metrics if they can't be written to the database
	- Serve a HTTP 503 code if we can't get data, rather than crashing
+ Allow notary public/private keys to be read from environment variables.
	Could be a security trade-off, but makes it easier to run notaries on some distributed systems.
+ Allow notary public/private keys to be exported as heroku config vars.
	Other systems could be supported as needed.