update JSON implementation from 2012-10-08 version of json2.js; applied D.C.'s changes thru-out, including the defense against window.prototype (which I think refers to var declarations shadowing window.prototype)

Fix bug where manually clicking the 'Check for updates' link in header_message.tpl would show the 'You are using the current version' message even if there is a new version.

Fixes #3131, add new auto-updating widget that displays the number of visitors, visits and actions in the last N minutes.

Notes:
  - Added visitors metric to result of Live.getCounters.

Fixes #3805, reverted change in log importer that looked for end-of-line after format regex match and modified format autodetection logic to pick the format based on whether the format matches and the number of groups returned in the match.

Notes:
  * Added several more tests to log importer tests.py. Added tests for checking format of log files w/ extra junk info on log lines. Added individual tests for parsing regex format.
  * Modified log files used in ImportLogs test, added extra junk info to end of some lines.
  * Fixed failing test in tests.py for the S3 log file format.

refs #3852

 * removed another for in loop
 * fixed very strange website selection error: "Can't move focus to the control because it is invisible, not enabled, or of a type that does not accept the focus."

refs #3332 fixing regression related to using ajaxHelper in transitions: use regular transitions callback when PHP throws an exception (e.g. NoDataForAction) to let transitions handle the error and show a message in the popover.

Reported in http://forum.piwik.org/read.php?5,101439

refs #3852

 * use a limit for the number of actions that are loaded for every visit. without a limit, the web server might crash (e.g. when there are 100K+ page views in one visit after a log import)
 * regular pagination in visitor log. (a) performance improvement: use indexes in the select query. (b) bug fix: the old logic was incorrect. in one setup, there are 10K+ visits but the visitor log only showed one full page and one page with one visit.
 * removed reference to trunk from tests read me

Updating search engines

Refs #3833 - Piwik_Period's toString method does not return the type of the Period and a "Array to String conversion" notice is triggered. So we use the getLabel accessor.

Add new translation to document the setting.

fixes #3828

Add new translation to document the setting.

fixes #3828