Merge pull request #78 from MontmereLimited/master

TimezoneType should be Unicode, not CHAR(50)
Fix py26 and py27 unicode handling for tz type
Fix indentation
Add comment
Add support for pk aliases
Add get_columns utility function
Fix WeekDaysType support for py33
Add get_columns to functions module main import
Add some code examples
Add get_columns to main import, bump version
Add ordereddict to py26 requirements
Add tests for primary_keys
Add aliases support for get_columns
Fix typo
Add more examples for primary_keys
Rename functions to better cope with naming standards
Add expression parser
Add create_tables test option
Bump version
Add absolute import, fixes #79