Add unit tests for new Metrics Formatter classes and remove existing ones. Small change to Overlay included and bug fixes to metrics formatting code included.

refs #5940 moved files into a subfolder framework, added autoloader to remove duplicated code to load autoload.php and to be able to register more autoloaders (eg for test files) on demand. This I got read of many includes that had to be updated all the time and that had to be updated all the time when moving iles

refs #5940 we might stay backwards compatible this way for 2 months. moved some tests from unit to integration and explained when a test is a unit test, an integration test or a system test.

refs #5940 put tests in correct folders, better testsuite names, some tests still fail and I cannot figure out why

Piwik is a free/libre analytics platform. Refs #4455 GNU Package requirement to use free/libre instead of open source

refs #4233 moving tests that require a database to integration as those are integration tests per se

Adding MetricsFormatter class which knows how to format/display metrics (time, money, size, etc)

And factored out code in ServerFilesGenerator.php

Added namespaces to functions.php files in the five plugins that had one
Work in progress

Refs #4059 Work in progress: Conversion to use Namespaces: Period*, Metrics, Segment, SegmentExpression, PluginsManager.
Removed some deprecated code.

Converting Access & Auth to namespace

Make Piwik_Access a singleton instance and remove use of Zend_Registry for the Piwik_Access singleton.

Implemented custom event dispatching system for Piwik (replaced event dispatcher lib in libs/Event).

Notes:
  - New dispatcher can execute callbacks before or after other callbacks.
  - It is also possible to dispatch events only to a specific set of plugins instead of all plugins.
  - Moved Piwik::unprefixClass to Piwik_Common::unprefixClass
  - Added visibility to some event handlers that were missing it.
  - Allowed two unit tests to fail w/ better diagnostic messages.

 * bug fix: min/max generation time didn't work in nested data tables because the column aggregation operations were not passed to sub tables
 * ui improvement: very small values were shown as 0s. use three decimal places if value is smaller than 10ms (e.g. display 2ms as 0.002s instead of 0s)

Small update to log analytics readme
Fixes #1700

Awesome work Timo!

 * adding avg_time_generation to Actions.get + integration tests
 * adding sparkline for average generation time to Visitors > Overview
 * changing number formatting to 0.XXs instead of XXXms + test cases
 * tooltip for reports with avg. generation time: "average based on X hit(s)"
 * log import: support generation_time_milli (not only generation_time_micro)
 * example for importing generation time from logs in read me