Linear regression model, Data dumps, and other minor additions.

This merge has the following changes:
 - Updated database schema. The repository table now has a last data dump field and there is a new table called glm_coefficients that holds the generalized linear regression model coefficients.
- We are now performing monthly data dumps into the analyzer/datasets/monthly folder in comma separated value format that can easily be imported into tools such as 'R'
- The metrics generator now also builds the linear regression model in addition to the median model. All linear regression coefficients are saved to database
- Email notifications are also sent to the cas.notifier instead of myself
- Github api credentials moved to the config file (example file modified to reflect this)
- Refactored out such that the models are separate in the analyzer (median vs linear regression)