Added bindings for the WarpOp's FilterType parameter's enum values.
Added the BoundMode parameter to the WarpOp.
The new parameter specifys how out-of-bounds pixels are sampled from the input image. A new option "SetToBlack" has been added which sets pixel samples that are out of bounds to black.
The default value is set to "Clamp" to ensure backwards compatability.
Tidied legacy code by removing unnecessary casts to "int" on the presets and removing unwanted enums.
Merge pull request #169 from goddardl/WarpOp

WarpOp boundMode parameter.