Added support for generator style Graphite functions. These are functions that
can be used in place of a whisper metric to create graphable data. The most
commonly useful generators are constantLine, threshold and events.
sinFunction, timeFunction and randomWalkFunction can be useful for
debugging.
Extracted generator metadata into its own class.
Enhanced Graphite_Graph_CallSpec to understand generators.
Enhanced Graphite_Graph_Series to understand generators.
Added support for generator style Graphite functions. These are functions that can be used in place of a whisper metric to create graphable data. The most commonly useful generators are
constantLine,thresholdandevents.sinFunction,timeFunctionandrandomWalkFunctioncan be useful for debugging.