Refactor Generated remove*() methods for CoughPHP

Refactor generated remove*() methods to use deletion strategy settable through config or by overriding a new delete() method.

Add Observer Pattern to DAL for CoughPHP

"as_database" currently supports query logging through methods startLoggingQueries(), getQueryLog(), etc. We should change this to use the observer pattern (and provide a couple query loggers to do what the old methods do).

Add SQL Server Database Support for CoughPHP

This will require either using another existing DB layer or making the needed changes to the "as_database" module so that it can support other drivers.