add a grep() method to the search class

[pascalchevrel]

Small note to add a utility grep() function to our search class. Because almost every time we prepare a regex it is to grep data into it so we end up with code such as:

$filtered_strings = preg_grep($search->getRegex(), $source_strings);

And this would be shorter and more readable IMO:

$filtered_strings = $search->grep($source_strings);

[pascalchevrel]

We are having an l10n hackathon mid-February and we will have a table with at least 4 people working on Transvision. I am putting that bug in the backlog of bugs to fix for the event.