merged branch Tobion/patch-3 (PR #613)

Commits
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e81a9e2 Improved random function

Discussion
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Improved random function

- dealing with empty array (otherwise PHP warning is raised)
- using array_rand() and thus saving the $keys variable

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by Tobion at 2012-01-25T12:41:32Z

How about allowing `mt_rand ( int $min , int $max )` with optional parameters to be used when the $values ist not an array?
This would solve use case #612