Remove messages.inc, rebuildLanguage.php, writeMessagesArray.inc

They are not being used anymore since the messages lists are in JSON
format, no idea why they were still here. Especially messages.inc is
just confusing everyone adding or removing messages.

Change-Id: If104ca1609e122b6871a97521065916a26734516
Merge "Remove messages.inc, rebuildLanguage.php, writeMessagesArray.inc"