#29.  Prevent fatal PHP error by checking for valid PDOStatement object.
 #29. Add an informative comment explaining PDO's unusual behavior with prepared statements.
Fix not nulls missing default values.  Tests would not run to completion in a clean installation due to these SQL DDL errors.
 #29.  Check for error return from execute() before trying to call any version of fetch().  If there is an error, the return value is 'false' instead of a valid instance of PDOStatement.  Without these changes, errors cause fatal PHP errors when, for example, $this->fetch() is execute without $this being a valid object.
Merge pull request #33 from cxj/tests

Tests fixtures: remove NOT NULL for table article fix #32
Merge pull request #34 from cxj/catcherrors

Suggested fixes to issue #29.
Merge pull request #36 from mta59066/master

execute() on update does not return number of updated rows fix #36
BUGFIX: Could not update tables with zero, blank or null values
Fix travis tests (CURRENT_TIMESTAMP replace with 0)

$ mysql -u root -D fblog < tests/fblog.sql
ERROR 1067 (42000) at line 9: Invalid default value for 'published_at'
Fixed return value of DeleteQuery execution
Merge pull request #40 from pkoutsias/patch

Fix #39: Add return value of DeleteQuery execution