Updates to implement finish, process MultiSmartData for v1.2 (Mobile) SmartData and MultiValue workflow support.

A search API has been created.
The Backend and the SmartAPI has been modified to support the search functionalities.
A search recieves a series as a parameter, one that do not necessarily specifies a unit. Similar to a workflow, a search type is defined per domain. Moreover, a 'options' parameter is also expected, specifying which type of search will be performed. If options is not presented, search of index 0 will be executed.
A search returns a multi-unit series, ordered by timestamp.

An example for tutorial domain is provided, where through search0 anomalous temperature values are detected in the space-time range specified by the series parameter.

on mu_put.php and mv_put.php we changed instantiation of Backend to support requests with certificate.
on put.php the extra newline that php was complaining about was removed.
on Backend.php was changed to adjust create series (fix algorithm that merge series),
and some bug fixes on multi SmartData insertion.
on Series.php throw exception if invalid values of t0, t1 and r was changed to include the values of these parameters.
on MultiSmartData.php: bug fix on verifying existance of ->uncertainty and adding a parseJson method.
Also, files Backend.php and SmartAPI.php were changed to support get_activity.