Changed JavaScript Tracking Code generation to use "//", instead of verifying whether the site is using "https", or not, and generating a corresponding URL.

"//" has been part of the RFC for well over 18 years. It has been confirmed to work in all major browsers (Firefox, Chrome, IE, Opera).

References:
- RFC 1808 Section 4: http://www.ietf.org/rfc/rfc1808.txt
- RFC 3986 Section 5.2: http://www.ietf.org/rfc/rfc3986.txt
- Stack Overflow QA 1: http://stackoverflow.com/q/4659345/238722
- Stack Overflow QA 2: http://stackoverflow.com/q/6785442/238722
First attempt at fixing failing tests.
Merge branch 'master' of https://github.com/piwik/piwik
Missed one correction on the failing tests.
Refs #3490 User ID Tracker is now working:
- new user_id field to contain the raw user id value
- new &uid= tracker api parameter
- add userId to Live API output
- added integration test
Refs #3490 User ID Tracking with Piwik.js + tests
Refs #3490 Encode user id value before sending to Tracking API.
Added the protocol-agnostic URL format to the Tracker's fallback image.
refs  #5995 Remove xhprof, and other phpunit dependencies, from the vendors to keep builds light
Add --no-dev flag to composer when installing dependencies and packaging Piwik releases
2.6.1 fixes  #6127
Update README.md

the right pull request
Fixed typo for Piwik 2.6.0
Merge pull request #6143 from piwik/translationupdates

[automatic translation update] Updated 62 strings in 1 languages (cs)
Fixing documentation formatting of Controller::renderTemplate().
Fixes #6128, fix opt-out iframe error (do not use renderTemplate since it will indirectly require the idSite query parameter). Includes new UI test.
Updating UI tests submodule (remove .only call).
Updating composer lock file (ran composer update).
Refs #6103, add logging for exceptions caught in View.php.
refs #6149 always require latest Piwik version when generating a plugin. Still todo: update plugin.json when generating a component. Also improved the controller example/template