Add resizer options for VapourSynth

[jul059]

There are already a great number of resizing options when using VapourSynth. I find myself using filter options that aren't already included in the presets like Hermite, which is one of the best filters for downscaling.

When adding a resize filter, there is already a prompt to select between bilinear, spline, etc. It would be great to add a few more that I find useful, such as Hermite, Lanczos2 and Lanczos3 (not sure what the default Lanczos is). This can be done simply by using the filter parameters. For example,

Hermite:
clip = core.resize.Bicubic(clip, %target_width%, %target_height%, filter_param_a=0, filter_param_b=0)

Lanczos2:
clip = core.resize.Lanczos(clip, %target_width%, %target_height%, filter_param_a=2)

Lanczos3:
clip = core.resize.Lanczos(clip, %target_width%, %target_height%, filter_param_a=3)

This would allow the use of those resizing filters without the need to know the parameters to pass as arguments. To me, it seems consistent with Staxrip's design.

Additionally, other filters that I don't use could also easily be implemented:

Catmull-Rom:
clip = core.resize.Bicubic(clip, %target_width%, %target_height%, filter_param_a=0, filter_param_b=0.5)

Sharp Bicubic:
clip = core.resize.Bicubic(clip, %target_width%, %target_height%, filter_param_a=0, filter_param_b=1)

Lanczos4:
clip = core.resize.Lanczos(clip, %target_width%, %target_height%, filter_param_a=4)