Add Ghostery-dodging javascript code

[bertrand-caron]

Hey There,

I implemented for my own use a way to prevent Ghostery from disabling the image tracker (link of the source given in commit body) that seems to be working well for me, feel free to add it to your repository.

Best, Bertrand

• Ghostery ignores the

[halfdan]

Hi Bertrand, apologies for letting this linger. I appreciate your work on this, however am not convinced it should be included in this gem. Part of Piwik's mission is respecting user rights and I feel like embedding code to dodge attempts to prevent tracking contradicts this.

I'm going to close this PR, but anyone who wants to use this can use this code to implement it themselves.