Connect to MySQL server in TRADITIONAL mode

Details are here:
http://dev.mysql.com/doc/refman/5.5/en/sql-mode.html#sqlmode_traditional
Show database-level errors in forms
Sort imports
Add [Positive]IntegerField validation

Also make out-of-range errors more consistent.
Add cyder/base/validators.py
Merge branch 'column-range-fix' of git://github.com/drkitty/cyder into drkitty-column-range-fix

Conflicts:
	cyder/base/views.py