DVC: Rename AllowMultipleSort() to AllowMultiColumnSort()
DVC: Code style changes
DVC: Rename AllowMultiColumnSort() accessor to IsMultiColumnSortAllowed()
DVC: Doc code style change
DVC: Rename AddRemoveMultipleSortColumn() to ToggleSortByColumn()
DVC: Code style changes in generic implementation
DVC: Don't use STL algorithms in generic implementation
DVC: Use wxCHECK_RET() macro instead of wxASSERT_MSG()
DVC: Code style changes in generic implementation
sample: Fix TAB issues
sample: Update code to reflect recent changes to DVC
sample: Better example for customization of mutli column sort

Now left click + ctrl will toggle multi column sort when custom
behavor of multi column sort is enabled.