Jira twin of: https://fogbugz.unity3d.com/f/cases/1392278

Problem statement

Current Gaussian filter implementation operates at 1 texel precision (1-5 texel range). This is a problem, because even at 1 texel radius, Gaussian filtering can produce overly blurry results.

Proposed solution

Increase Gaussian filtering precision to 0.1 texels. Gaussian filter in Adobe Photoshop operates at that precision as well.