Added support for the divide folder

The divide folder is meant to provide saving filters for the purpose of
dividing images into block sections. 16x16 and 32x32 will be some of the
formats
Added the initial files for image division converters
Fixed save support in MainForm-ApplyFileFormatOperation.cs

I had forgot to implement it
Added the base class for image division
Added a constructor to ImageDividerConverter.cs
Added SquareDividerConverter class

This class is meant to handle the cases where the tiles are squares. This makes
it so that only one property has to be overriden. This property is the side
length which represents the length (in pixels) of a side of the square.
System.Collections is now imported
Updated the summary for square divider
Added plugins for the standard square divider resolutions
Fixed a compiler error in ImageDividerConverter.cs
Fixed a file write issue where files were continually being overwritten
Fixed the naming scheme for image division

I was not computing the offsets for tile id correctly. This would cause files
to be overwritten because the names were the same.
fixed image naming once and for all by introducing a k variable for counting