Provide a way to suppress the cell divider in NICellBackgrounds using a category method on UITableViewCell.
Use NIGroupedCellAppearance protocol instead of category method to suppress the cell divider.
Change drawCellDivider to drawsCellDivider in the NIGroupedCellAppearance.
Fix the comment style in NIGroupedCellAppearance.
Merge pull request #396 from jverkoey/cell_divider

Provide a way to suppress the cell divider in NICellBackgrounds.