.RoundCorners Method Update

[Salcave]

Hello,

The output string of the .roundCorners method is outdated and needs to be changed from "round_corners(a|b,r,g,b)" to "round_corner(a|b,r,g,b)."

Also, the thumbor docs reference a "transparent" string that can be added as part of the arguments to make the cropped off result transparent. If this could be added it would be great.

Thanks!

Sal Solis