/**
* Most machine names are generated as-you-type via Javascript helpers on the
* client side. This helper function automates server-side conversions from
* regular text strings into valid Drupal machine names.
*
* Machine names must contain only lowercase alpha-numerics and underscores.
* Non-alphanumeric characters are converted to underscores, and sequential
* underscore characters are trimmed to a single character.
*
* Additionally, if the transliteration module is enabled, then it will be
* used to first convert non-ascii Unicode characters to standard Roman ASCII
* characters on a best-effort basis, and replacing all unknown characters
* with underscores.
*
* @param $text
* A string of characters to be converted.
*
* @return
* A string containing the valid Drupal machine name for the specified text.
* Returns the empty string if invalid input was provided.
*
* @see
* See the transliteration module in the drupal contrib repository for more
* information on non-ascii character transliterations.
*/