added ability to configure multiple panes around the map - top,bottom,left,right as well as original 'sidebar'.
added new widget type 'contentPane' to enable loading a widget as a contentPane into one of the new panes.
refactoring the pane config to simplify.
passing multiple arguments to lang.mixin.
correcting the name of the `_createContentPaneWidget' function.
fixing some whitespace.
adding an id for the sidebar pane.
remove the inner BorderContainer
Merge pull request #121 from DavidSpriggs/feature/multiple-pane-configuration

added ability to configure multiple panes around the map