See https://github.com/piwik/piwik/issues/9419#issuecomment-166764396

Tests show that processing minimum event value  works correctly
Fixed tests in plugins/AnonymousPiwikUsageMeasurement

as suggested in code review

fixes #9194 fix "goal can be only converted once per visit" is not respected when segmenting goals with a log_link_visit_action segment

fix error table log_visit is already joined in https://github.com/piwik/plugin-CustomDimensions/pull/19

Check whether string actually contains value to prevent from copying the string to reduce memory usage

This reverts commit 745c6c6d.