Ability to log sql query via boolean from Sql2o or Query classes

[sachin-walia]

This is a simple request but one could avoid writing pesky log statements in multiple places to log sql query.

My take:

1. To define it globally we can make use of Sql2o class.
2. To define per query provide an ability in Query class.

Sql2o and Query both could provide a method something like:
setSqlLogging(boolean enable, LogLevel ..);

Log Level could decide which level should be used for logging SQL. Default could be debug / error.

[aaberg]

I like this idea very much! I will definitely add this at some point.

[aaberg]

I have added logging of the SQL just before the statement is executed. It will log the parsed query, so that parameters are logged as ?. Instead of adding a setSqlLogging() or similar, it will simply log queries at DEBUG level, so that it utilizes default logging behavior.