Removed column picking code. Code lives on column_picking branch.
Merge pull request #1322 from crobinsonut/column_sorting

Column sorting: Name Only
Added preferences to openmdao namespace.
Added argument to ColumnPicker constructor for setting default visible columns.
Adjusted PropertiesPane to set default visible columns per component editor.
Added support for viewing more columns in component editor. Columns visible by default are info, name, units, value and description.
Columns settings for inputs/outputs tabs per component editor are stored and recalled per session.
Removed modification from SlickGrid api. Cleaned up preferences saving and recalls in PropertiesPane.
Adding column header test functionality to grid pageobject. Columnpicker dom elements are removed when component editor is closed.
Merged out.
Column picking fully working and verified with test.