Add support for complex DateTime operations on SQL.

[cyilcode]

Currently the only thing that you can play around with DateTime structs is just its complete values. You are not able to query stuff like

?o=eq&p=myDateTime.Day&v=10

Query above should work well if the data source is in memory but it is not possible on SQL data sources since SQL won't understand what .Day would mean.

Also, we should be considering the fact that not all SQL platforms offer the same DateTime operations. For example, extracting Day from a datetime sql column goes as

SELECT DAY(myDateTime ) from MyTable on MSSQL.

However, this is not the case for every SQL platform.