refactor the way we grab settings interally; set the defaults in one place. Also, make sure tests know about all the settings
app_settings should always default to django's settings if they exist;
so building this as a class taht always does the lookup first.

Also, added some constant values for metric granularities, and moved the
key/date format patterns here.
use the new app_settings object, and respect the min/max granularity settings
use override settings instead of doing that manually (and incorrectly); added tests for new R methods
testing the new AppSettings
oops; just the correct default port for redis
more updates to respect granularity settings
use get_r instead of the R class directly in the template tags libs
keep the order for the metrics dict
updating tempaltes/template tags for metric_details
replace R() with get_r() in views
only list the configured granularities in the templates
updating README and HISTORY
dropping support for 1.5
version bump
use get_r in the management commands
BEAT GLOBAL STATE!
Stackoverflow says don't do this at the module level anymore :-/
add MIDDLEWARE_CLASSES to the test settings
I'm ocd