Add call to Donation in Piwik - Piwik is Free, but we need your support #3624

• Add a donate popover in Piwik, using the akismet-like slider
• Where to display?
  • Display this call to Donation after successful piwik upgrade
  • Also display at the end of the installation
  • Link to open the popover in the "About Piwik" panel
  • Add an "About" tab in the admin menu, that will give some info about Piwik call to donate
  • also in General Settings, DB Usage, Give us Feedback link
  • add a donation button to the release blog posts... Like "If you like those new features/ this release, feel free to donate some money" + Call to crowdfund
• Donation includes
  • Paypal donate
  • Flattr, things
  • Crowdfunding

Please suggest if you have any idea to help us reach Piwik 2.0 faster and generate revenue to pay for Piwik developers!

[7746] fixes this.

Awesome result Benaka well done!!