Add calendar year dimension sql
Add race dimension sql dimension code
Add debug mode and change interface of data gens

There is now a debug flag which causes generateDataFromSql to make no
actual database queries. Instead it records the queries that would
happen (after rendering and translation) to a log file.

Furthermore, the interface of generateDataFromSql has changed to take
all of its parameters instead of having default parameters within the
DataGenerators.R file.
Remove boilerplate sql code in dim files

Until now the user was required to build the dim table herself in the
each dimension sql file. This meant that the initial code of every
dimension sql file was identical. This redundancy was removed.
Remove required sql in examples/

The required sql found in the examples/ folder was taken directly from
CohortMethod, but that sql produces very sparse data which is sparser
than what HDPS is meant to use in its algorithm. These need to be
rewritten to fit into the HDPS paradigm.

In addidtion to this, there is now a check done by
prioritizeOptCovariates() to see if no optional covariates were
generated by the sql. The previous code would have resulted in an error
in that situation.