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 #6136 from MichielDeMey/patch-1

Fixed typo for Piwik 2.6.0
Merge pull request #6131 from ahattouti-canaltp/patch-2

Update README.md
updated the comments in the menu template
fixes #6153 check whether the defined module and action actually exists if development mode is enabled
refs #6133 added a command to clear all caches
refs #6133 consistent naming
Merge branch 'master' of github.com:piwik/piwik

Conflicts:
	core/Version.php