Reporting Phase I: Take II

Create a reporting dashboard and two attendance reports.

* Add Reporting pagelet to the admin dashboard:

![selection_0087](https://cloud.githubusercontent.com/assets/7445602/4144888/faf45782-33ea-11e4-9520-0efbb66818f3.png)

In order to see the reporting pagelet, a user must have the "Run Reports" flag set in the Administrators page, or be a Super Admin.
![selection_0091](https://cloud.githubusercontent.com/assets/7445602/4144982/7cbf6520-33ed-11e4-81cb-e2aaeb7f4a82.png)
 
* Created "Reporting Dashboard" to launch reports 
![selection_0088](https://cloud.githubusercontent.com/assets/7445602/4144934/fb8843a6-33eb-11e4-9f74-64b956d01ba3.png)

* Created two attendance reports:

 1. Attendance Totals
![selection_0089](https://cloud.githubusercontent.com/assets/7445602/4144936/045e2e8c-33ec-11e4-8465-e0ccc22dd48b.png)

 2. Weekly Attendance Detail

![selection_0090](https://cloud.githubusercontent.com/assets/7445602/4144938/0be6396a-33ec-11e4-8060-671ce29690be.png)

The Weekly Attendance Detail report assumes that we are only interested in the current members of the group to report "misses". Reporting historical "misses" is not advised, as the group composition is only known at the current date.

This might be a bit of an edge case, but if there is a person who is in more than one group that is reported during the period, and they have attended one group and not the other, then the missed attendance might not show.

I haven't done any tests specifically, as there were only two controllers and it didn't seem worth it given they have probably already been tested by dossier's authors. Happy to oblige if you think some tests are needed.

Also just noticed because I committed my changes prior to merging  master to my reporting branch locally, that there's now a lot of lines in this commit... happy to work on tidying that up too.

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