Better spacing for RSS feed

Added tests for anonymous usage tracking

Command to invalidate archive data (w/ period cascading)

Fix logo when a custom logo is uploaded

Left menu tweaks

Make sure to remove no longer needed plugins leftMenu and ZenMode

fix "Check for updates" button not working on demo

Rename InvalidationResultInfo to InvalidationResult and remove Period::getAllParentPeriods and replace its use in ArchiveInvalidator w/ some small SQL changes.

Fix regression, make sure if period is not supplied to ArchiveInvalidator then all periods are invalidated efficiently.

Don't use switch in core:invalidate-archive-data command, instead add new non-API method to Piwik Core.

Add initial command to invalidate report data w/ unit test (integration test coming in later commit).

Make ArchiveInvalidator an immutable service and add it to DI. markArchivesAsInvalidated (or whatever it's called) now returns an instance instead of an array of output messages.

prevent flicker of menu category when there is no  menu item for that category, instead remove it server side

number format in all websites