Merge pull request #77 from developerauction/master

Fix calls to order_unsupported.
Fix reversing order given as block
Simplify function arguments
default_column_options
doc
filter_by method
Column order_by_value option
Refactor tests
Ability to pass options to column names filter
Inspect method for column class
Rename method
Improve datagrid warnings
Merge branch 'master' of github.com:bogdan/datagrid
Dynamic filter
Improve tests and doc
multiple separator support
Dynamic filter localization
Improve no results spec
Move default localizations to yaml file
Support multi-value filter in form builder