modified gitignore
Refactor last year chart

Pulled some instance variable assignment into the controller.

Also extracted a method regarding interpolated values for the present
month.
Extract behavior from Todo.from_rich_message

`Todo.from_rich_message` was partially tested from the MessageGateway,
but it is mostly untested and does not belong in Todo due to it's unique
nature. Extract it entirely from `Todo` into it's own dedicated object
for unit testing.
use a null object like a boss
TodoFromRichMessage is really a service object
fixed next month label for calendar view
Pull out RichMessageExtractor

No need to have it embedded
  when it should be unit tested!
Shifting more instance variables to the controller

Also removing some instance variables that were never invoked in the
views. This sets up a future refactoring of the method of comptuting
rolling averages, which differs between the two types of "last year"
views being refactored.
Merge pull request #191 from doncruse/master

Refactor last year chart
Merge pull request #192 from crymer11/master

use a null object like a boss
Merge pull request #194 from stacyvlasits/master

fixed next month label for calendar view
Merge pull request #193 from mattdbridges/extract-rich-message

Extract behavior from Todo.from_rich_message
Removing some intermediate values

This removes some intermediate steps that were ultimately not necessary
to the math.  It also consolidates some of the methods for counting events
so that fewer intermediate values are necessary.

To that end, a new scope is added to the ToDo model for events that are
*either* created_at or completed_at after a certain date. This scope
allows the StatsController to pull out the largest possible responsive
set of values, and then filter just the particular slices that it needs
for various steps in the calculation.
Removing some more intermediate values

Also removing the python-esque combination methods to set multiple
disparate variables from a single method by refactoring that to a
simpler method.

Reducing the complexity of computing running averages.

Note: It is not clear to me why the actions_done_lastyears_data
action is entirely unscoped on date. That seems to be the expected
behavior, so I left it alone.
Combining the running average methods
Removing a single-line method
Tweak to running averages
Simplufying interpolation method
Moving time labels to separate methods
Moving label creation to helpers