[Safari] Toolbar icon isn't pixel-fitted on non-retina screens.

[franzf]

Steps to Reproduce

Install uBlock, add button to Safari toolbar.

Symptoms

Icon looks nice on Retina screens, blurry on non-retina screens.

Compare, retina:

Non-retina magnified 2x:

The U is way blurrier than the rest of the sharp lines in the other icons. This blog post explains what I mean by pixel-fitting: http://dcurt.is/pixel-fitting

uBlock version:
    0.9.2.0
Browser and version:
    Safari 8.0.4
OS and version:
    10.10.2

[chrisaljoudi]

@franzf fixed in 46b786d. Thanks.