string imap_utf7_decode (string text)
Decodes modified UTF-7 text into 8bit data.
Returns the decoded 8bit data, or false if the input string was not valid modified UTF-7. This function is needed to decode mailbox names that contain international characters outside of the printable ASCII range. The modified UTF-7 encoding is defined in RFC 2060, section 5.1.3 (original UTF-7 was defned in RFC1642).