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

 * DataTable_Row::sumRow has a new parameter $aggregationOperations which allows treating columns as min or max (not only sum)
 * The aggregation operations can be set on any data table or passed to ArchiveProcessing_Period::archiveDataTable()
 * The Actions plugin uses the mechanism to aggregate the new metrics as min and max
 * The metrics are in the API output but not in processed reports
 * The min/max values are shown in the tooltip that appears when hovering the average generation times
 * Integration test updates

 * 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

git-svn-id: http://dev.piwik.org/svn/trunk@7259 59fd770c-687e-43c8-a1e3-f5a4ff64c105

 * Adding new API functions to fetch a specific URL, page name, download or outlink, without the complicated logic of fetching sub tables, etc.
 * Refactoring a bit of code in Tracker and adding integration tests for these new methods

git-svn-id: http://dev.piwik.org/svn/trunk@3736 59fd770c-687e-43c8-a1e3-f5a4ff64c105