* linking on metric value
* Display + linking on "Majestic"

Fix notice when there is no data
Delete sum_time_generation column from output + Fix tests. This data point can be obtained by AVG_TIME * HITS_WITH_TIME so not so useful in output

Fixing bug on dev machine SQLSTATE[42S22]: Column not found: 1054 Unknown column '%' in 'where clause'"
Fixes #3811

 * rename custom_float_1 DB field to custom_float (further time tracking can be tracked as events)
 * fix regression missing auth in Live
 * remove extra comma in javascript which breaks IE parsing

Correct ISO3toContinent mapping

fixes #3864

Converting Piwik core source files, PHP, JS, TPL, CSS

More info: http://piwik.org/participate/coding-standards/

Code cleanup.

This is an example plugin and it should serve as a good example :)

 * by default, send performance.timing.responseEnd - performance.timing.requestStart as generation time with the tracking request
 * if the performance.timing API is not supported by the browser, don't send the metric
 * new method disablePerformanceTracking()
 * new method setGenerationTimeMs(generationTime) to set the generation after measuring it on the server side 

added a little debugging output to datatable_manager.

CORE

 * formatting sub-second times
 * getColumn() method on data table array (in order to behave the same as the regular data table class)
 * data tables can store in their meta data, which columns are empty (this is used in order to dynamically hide the new "generation time" column)
 * ViewDataTable and Api.getProcessedReport act according to the empty column meta data


SCHEMA

 * new column custom_float_1 in log_link_visit_action
 * new version to apply the change


TRACKER

 * Piwik_Tracker::setGenerationTime
 * tracking parameter "generation_time_me"
 * value is stored in new custom_float_1 column
 * the log importer can handle a group "generation_time_micro" which can be used in a custom log format. _micro is used because apache can log the time in microseconds but piwik processes milliseconds.
 * note: extension of JS tracker still missing


ACTIONS PLUGIN

 * for pages and page titles, add new columns sum_time_generation and nb_hits_with_time_generation to the blob archives
 * if they are set, compute avg_time_generation on the API level. if not, remove the columns and mark them as empty in the data table meta data.
 * show new column "avg. generation time" in the pages and page titles reports


plus TESTS for everything

Hopefully fix test now.

refs #3734

Fixes #3734, added 'external backlinks' and 'referrer domains' stats to SEO widget via Majestic SEO API.